TIGER/Line(TM) Files, 1992 Chapter 4: Geographic Entities Overview Introduction The 1992 TIGER/Line files contain the boundaries of the legal entities certified as legally in effect on January 1, 1990, most of the statistical entities for which the Census Bureau tabulated the data from the 1990 census, such as blocks, census tracts, and census designated places (CDP's), and the post-1990 changes and corrections. The files include the codes used in the 1990 decennial census, corrections to these codes, and codes for new entities. The TIGER/Line(TM) files also contain select legal and statistical entity codes used during the 1980 census. See Appendix F for the number of legal and statistical entities. The inventory and boundaries of the current political entities included in the post 1990 changes are those reported in the 1992 Boundary and Annexation Survey and depict for the most part, the inventory and boundaries in effect as of the January 1, 1992. There are some areas for which the Census Bureau obtained post-January 1, 1992 information. Census geography is hierarchical; Figure 4-1 shows the progression of geographic areas from the Nation to the block level. Figure 4-2 provides an example of the geographic relationships for small-area statistical entities, and Figure 4-3 provides an example for legal and statistical entities. The TIGER/Line(TM) files identify geographic entity codes in two ways: * The assignment of codes to the right and left sides of the complete chain, and * The identification of codes that belong to each GT- polygon. Some 1990 geographic entities such as State, county, county subdivision, place, census tract/BNA, and census block are identified in both complete chain and polygon records. Boundary and Area Changes Since the release of the1990 Census TIGER/Line files, the Census Bureau has shifted and reshaped some line features including boundary lines. These changes involve the realignment of complete chains associated with corporate boundary corrections and current changes. The maps used by the local officials to identify boundary changes may include additional changes to the shape and position of other features effecting other statistical entities (including census tracts/BNA, blocks, and so forth). The shape and area of the 1990 geographic entities depicted in the 1992 TIGER/Line files may differ from the earlier version. However, the inventory of 1990 census tabulation entities will remain the same. Changes to the shape and location of complete chains also will change the polygon interior point coordinates. Codes for Entities The list of FIPS State and county codes appears in Appendix A. A list of valid codes and names for legal entities (e.g., places and county subdivisions) other than counties and county equivalents does not appear in the 1992 TIGER/Line file documentation. The TIGER/Line(TM) Geographic Names files list geographic entity codes and names, and is available as a separate data product. This product replaces the TIGER Geographic Reference File--Names, 1990 (PUBGRF90). Also see FIPS Publication 55-3, CODES FOR NAMED POPULATED PLACES, PRIMARY DIVISIONS, AND OTHER LOCATIONS OF THE UNITED STATES (FIPS PUB 55-3) for a list of entity codes, names, and class codes that identify each entity's type and status. FIPS PUB 55-3 describes the updated FIPS standard used for the 1990 census. A description of the Census Bureau's geographic codes for its "high-level" legal and statistical entities appears in the TIGER/GICS(TM) (Geographic Identification Code Scheme). The TIGER/GICS contains both FIPS and Census Bureau codes and names for an inventory of the geographic entities in the census. GEOGRAPHIC ENTITIES AI/ANA's Identification The AI/ANA's are represented in the TIGER/Line(TM) files by both a 5-numeric character FIPS code field and a 4- numeric character census code field. The TIGER/Line(TM) files use a single set of fields to identify a series of legal and statistical AI/ANA's: Legal Entities * American Indian reservations (AIR's) are legal entities having boundaries established by treaty, statute, and/or executive or court order. They are identified by either the Bureau of Indian Affairs (BIA) for Federal reservations or the individual States for State reservations. * American Indian trust lands included in the census are the off-reservation lands associated with a specific tribe or reservation held in trust by the Federal Government. They are identified by the BIA and State governments. Trust lands may be either tribal (held in trust for the tribe) or individual (held in trust for an individual member of the tribe). Trust lands are assigned the same codes as the reservation. Trust lands not associated with a reservation are assigned codes based on the tribal name. The TIGER/Line(TM) files do not distinguish AIR's and trust lands with the same code. Statistical Entities * Alaska Native village statistical areas (ANVSA's) are 1990 census statistical areas that delineate the settled area of each Alaska Native village (ANV). ANV's consists of tribes, bands, clans, villages, communities, and associations that are recognized in pursuant to the Alaska Native Claims Settlement Act (PL 92-203), but do not have legally recognized boundaries. Officials of Alaska Native Regional Corporations (ANRC's) and other knowledgeable officials delineated the ANVSA's for the Census Bureau for the purpose of presenting census data for these entities. * Tribal designated statistical areas (TDSA's) are geographic areas delineated for 1990 census data tabulation purposes by tribal officials of federally and State-recognized tribes outside of Oklahoma that do not have a legally defined reservation or associated trust lands. They define areas only for data presentation purposes that generally contain population under tribal jurisdiction and/or for which the tribe provides benefits and services to its members. * Tribal jurisdiction statistical areas (TJSA's) are geographic areas delineated for 1990 census data tabulation purposes in Oklahoma by federally recognized tribes that do not have a legally defined reservation. They define areas only for data presentation purposes that generally contain American Indian population over which one or more tribal governments have jurisdiction. They replace the single "Historic Areas of Oklahoma (excluding UA's)" recognized for the 1980 census. Record Locations: AI/ANA Codes RT Field Name Description 1 FAIRL FIPS PUB 55-3 code (left side of complete chain) 1 FAIRR FIPS PUB 55-3 code (right side of complete chain) 3 AIRL 1990 census code (left side of complete chain) 3 AIRR 1990 census code (right side of complete chain) A FAIR FIPS PUB 55-3 code (polygon) F FAIR90 FIPS PUB 55-3 code for a polygon with corrected 1990 code(s) G FAIRCU FIPS PUB 55-3 code for a polygon with updated code(s) from boundary changes since January 1, 1990 Codes: AI/ANA's Please refer to the TIGER/Line(TM) Geographic Names files, FIPS PUB 55-3, or the Census Bureau's TIGER/GICS for a list of valid codes and entity names. A range of census codes is allocated to each type of AI/ANA: AIR "0001" to "4989" TJSA "5001" to "5989" ANVSA "6001" to "8989" TDSA "9001" to "9589" Note: The data fields are blank if there are no AI/ANA's. ANRC's Identification ANRC's are corporate entities established by the Alaska Native Claims Settlement Act (PL 92-203) to carry out business and nonprofit operations for Alaska Natives. The 12 ANRC's have specific boundaries and cover the State of Alaska except for the Annette Islands Reserve. Record Locations: ANRC Codes RT Field Name Description 1 ANRCL 1990 census code (left side of complete chain) 1 ANRCR 1990 census code (right side of complete chain) Codes: ANRC's Please refer to the TIGER/Line(TM) Geographic Names files or the TIGER/GICS for a list of valid codes and entity names. Note: The data field is blank if there are no ANRC's. Block Groups (BG's) Identification * Geographic BG's are clusters of blocks, within the same census tract or BNA, having the same first digit of their 3-digit block numbers; for example, blocks 101, 102, 103,...,199 in census tract 1210.02 belong to BG 1. BG's never cross county or census tract/BNA boundaries, but may cross the boundaries of county subdivisions, places, UA's, VTD's, congressional districts, and AI/ANA's. BG's generally contain between 250 and 550 housing units. Each BG usually covers a contiguous area. Each census tract/BNA contains at least one BG. BG's are uniquely numbered within census tract/BNA. * Tabulation BG's are geographic BG's split to present data for every unique combination of county subdivision,place, UA's, VTD's, congressional districts, U/R, and AI/ANA's shown in the data tabulation products. The TIGER/Line(TM) files do not have a separate BG data field. Data users can determine the geographic BG by using the first digit of the block number and the tabulation BG by using the geographic BG in combination with the codes for the entities listed above. STF 1A and 3A present data for both geographic and tabulation BG's. Record Locations: BG Numbers See the section on census blocks for record locations and field names. The BG is the compilation of all blocks with the same first digit of their block number in a specific census tract/BNA. Codes: BG's Number: "0" to "9" Note: All polygons have a non-blank BG number. The left and right side complete chain block numbers should not be blank except where they are located along the outside edge of the county boundary. The TIGER/Line(TM) files do not contain codes for areas outside the county file. Some BG's may have a number equal to "0" in some coastal and Great Lakes waters. Rather than extending the census tract/BNA boundary into the Great Lakes or out to the three-mile limit, the Census Bureau closed some census tract/BNA boundaries along the shoreline or just offshore. The Census Bureau assigned a default census tract/BNA number "0000" and block number "099" to the offshore areas. Census Blocks Identification Census blocks usually are small areas bounded on all sides by visible features such as streets, roads, streams, and railroad tracks, and by invisible boundaries such as property lines, legal limits, and short imaginary extensions of streets and roads. Blocks never cross county or census tract/BNA boundaries. In rare instances, parts of a block may be discontiguous, but all parts of a tabulation block will be in the same geographic or governmental unit. Blocks are composed of one or more GT- polygons; that is, several GT-polygons can share the same block number. Census Block Numbers - - Blocks are numbered uniquely within each census tract or BNA. A census block is identified by a 3-character basic block number field and a character block suffix field. The suffix field often is blank. The 3-character basic block number identifies the "collection" block used in the 1990 census field operations. The first digit of the basic block number identifies the BG. The Census Bureau refers to the combined basic collection block number and suffix (if a suffix exists) as the "tabulation" block number. The 1990 tabulation block numbers identified in Record Types 1 and A have a 1-character suffix field. The corrected 1990 geography identified in Record Type F allows for a second suffix character. See the section below on Correction block suffix for 1990 corrected geography for examples of tabulation block suffixes. The suffix character is blank for whole collection blocks that also are tabulation blocks. Block numbers with suffixes usually represent collection blocks that were split in order to identify separate geographic entities that divide the original block. For example, when a city limit runs through collection block 101, the portion inside the city is tabulated in block 101A and the portion outside in block 101B. Water Blocks - - A 3-character basic block number that ends in "99" signifies water area. As there is only one number ending in "99" within a BG, many water polygons can have the same block number. Water blocks have suffixes if parts of the same block are located in different geographic entities. Rather than extending the census tract/BNA boundary into the Great Lakes or out to the three-mile limit, the Census Bureau closed some census tract/BNA boundaries along the shoreline or just offshore. The Census Bureau assigned a default census tract/BNA number "0000" and block number "099" to the offshore areas. Note that blocks in the default census tract/BNA's may have numbers other than "099." Water blocks do not appear in the 1990 census STF's files. Census maps and data files do not display the block numbers for water areas. The principal purpose for census block numbers assigned to water areas is to identify all areas of the United States and its territories and to allocate the water areas to geographic entities. Water GT-polygons with the same block number may not be contiguous to each other, but these GT-polygons will be in the same geographic or governmental unit. Changes to boundaries made since the release of the 1990 Census TIGER/Line files have altered or removed block boundary features between parts of some water blocks and have changed the block numbers (the BG designator) for parts of some blocks affected. Because these water blocks have no population or housing, the tabulation of the 1990 census is unaffected. Some water blocks in the 1990 Census TIGER/Line files Supplemental CD-ROM may contain census block suffixes that do not match the 1992 TIGER/Line files. 1980 Census Blocks - - The TIGER/Line(TM) files contain 1980 block numbers for the primarily urban parts of the Nation that were block numbered for the 1980 census and covered by the GBF/DIME-Files. The TIGER/Line(TM) files may contain 1980 block numbers for portions of the country where the Census Bureau did not tabulate 1980 census data by block and BG. These situations occur because these portions of the Census TIGER data base originated from the parts of the 1980 GBF/DIME-Files that extended beyond the 1980 block-numbered area. Data users concerned about the validity of 1980 block numbers are advised to discard all 1980 block numbers that do not correspond to block numbers in the 1980 STF 1B. In addition, the 1980 block number shown in the TIGER/Line(TM) files for a GT-polygon may not agree with the number used in the 1980 census for the equivalent area. Sometimes more than one 1980 block number fell within the same polygon in the Census TIGER data base; the Census Bureau made changes to the 1980 block assignments in order to insert the 1980 block numbers into the Census TIGER data base. If the street pattern changed between 1980 and 1990, the block numbers will be different. Data users concerned with the correctness of 1980 block numbers are advised to check them against the maps published with the 1980 Block Statistics Reports, the Metropolitan Map Series. Note: The 1980 block numbers do not have a block suffix. Corrected 1990 Block Numbers With a Second Suffix - - Record Type F contains corrected geographic entity codes. After the initial release of census counts, a number of governmental unit boundaries were corrected. These revised boundaries may have cut through an existing block. To provide the correct population and housing counts for the governmental units, the Census Bureau had to create additional blocks. Because the newly split blocks may have already had a block suffix, the Census Bureau retained the original suffix and added a second suffix to identify each part of the new split. Record Type F has a 2-character suffix field reserved for the original and second correction suffix. The second suffix is reserved for the correction block suffix; blocks that had no suffix before correction may receive a second suffix, but not a first suffix. Some boundary corrections did not split any 1990 tabulation blocks, so Record Type F may not include a second suffix for the block, even though space is reserved for one. Current Geography - - Record Type G identifies geographic entity changes from the 1992 Boundary and Annexation Survey. It does not show new block numbers. Even though the Census Bureau continues to conduct its Boundary and Annexation Survey to identify postcensus changes to the boundaries of legal entities, the 1990 and corrected 1990 block numbers remain in effect for all new polygons created by the postcensus boundary changes. The Census Bureau will not systematically update block numbering to reflect current geographic boundaries until it prepares for the 2000 census. Record Locations: Census Block Numbers RT Field Name Description 1 BLKL Basic no. and suffix (left side of complete chain) 1 BLKR Basic no. and suffix (right side of complete chain) 3 BLK80L 1980 basic no. (left side of complete chain) 3 BLK80R 1980 basic no. (right side of complete chain) A BLK Basic no. and suffix (polygon) F BLK90 Basic no. and double suffix for a polygon with corrected 1990 code(s) Codes: Census Blocks land blocks: First character = BG number: "1" to "9" 2nd and third characters: "01" to "97" water block (blocks ending in "99"): First character = BG number: "0" to "9" 2nd and third characters: "99" Note: Coastal water blocks may have the default BG number "0" (see the section on Water Blocks above). Note: Block numbers ending in "98" were not used. Note: All polygons have a non-blank basic census block number. The left and right side complete chain block numbers are not blank except where they are located along the outside edge of the county. The TIGER/Line(TM) files do not contain geographic codes for the area outside of the county file. The TIGER/Line(TM) files identify boundary complete chains by placing a "1" in the single-side segment field in Record Type 1. Tabulation block suffix (first character): Codes for land blocks with a suffix: "A" to "Y" Codes for water blocks with a suffix: "A" to "Y" "a" to "y" Code for blocks without any suffix: " " Code for blocks (see the section on crews-of-vessels for an explanation of the codes): "Z" Correction block suffix for 1990 corrected geography (Record Type F): Codes for second suffix (second character): Codes for land blocks with a suffix: "A" to "Y" Codes for water blocks with a suffix: "A" to "Y" "a" to "y" Code for blocks without any correction suffix and crews-of-vessels blocks: " " Filler for tabulation block suffix when the correction block suffix is used, but there is no tabulation block suffix "*" Examples: "102 " Census block with a blank tabulation block suffix. This block has not been split by any tabulation boundary. The tabulation block number is the same as the collection block number. "102B " Census block with only a tabulation block suffix (B) and a blank correction block suffix. This block may have received a corrected 1990 geographic entity code, but the corrected boundary does not split the block. "101BA" Census block with a tabulation block suffix (B) and a correction block suffix (A) resulting from a correction to the boundary of a 1990 geographic entity. The corrected boundary splits tabulation block 101B requiring a new correction block suffix for each part of the original block 101B. For example, block 101B is split into blocks 101BA and 101BB. "101*A" Census block with no tabulation block suffix, but a correction block suffix (A) resulting from a correction to a 1990 geographic entity. The corrected boundary splits block 101 requiring a new block suffix for each part of the original block 101. For example, block 101 is split into blocks 101*A and 101*B. Census Tracts and BNA's Identification * Census tracts are geographic entities within a county (or statistical equivalent of a county) defined by a committee of local data users. When first established, census tracts should have relatively homogeneous demographic characteristics. Generally, census tracts have a population size between 2,500 and 8,000 people, and average about 4,000 people. The committee of local data users can delineate census tracts for special land uses, such as military installations and AIR's. * BNA's are areas delineated by State agencies and/or the Census Bureau for counties without census tracts. The delineation of BNA's follows the same basic criteria as census tracts. Because BNA's appear more often in lightly populated counties, they may have fewer people. Numbering - - The TIGER/Line(TM) files store census tract and BNA numbers in a 4-character basic number field and an optional 2-character suffix number field. The Census Bureau uses a decimal point "." to separate the basic number from the suffix, however, in the TIGER/Line(TM) files, the decimal point is implied. The basic number and the suffix appear together in a single 6-character field. A basic number smaller than 1000 will contain leading zeros. Leading zeros are shown on machine-readable products; they are not part of the basic number, and they are not shown in printed reports and on census maps. The TIGER/Line(TM) files reserve the right-most two characters in the census tract/BNA field for the suffix. These two characters are blank if the census tract/BNA number does not have a suffix. Suffixes smaller than 10 have a leading zero, for example, census tract 0077.01. The Census Bureau uses suffixes to help identify census tract changes for comparison purposes. Local census statistical areas committees (CSAC's) have an opportunity to review the existing census tracts before each census. If a committee splits a census tract, the split parts usually retain the basic number but receive different suffixes. In a few counties, the committees approved major changes to the census tracts and renumbered the census tracts. Note that changes to census tract boundaries usually do not result in census tracts numbering changes. The Census Bureau documents changes to census tract boundaries but reports only a selection of the changes in print. Data users are cautioned to compare the census tract boundaries before making comparisons using 1980 and 1990 data. Boundaries and Boundary Changes - - Census tract/BNA boundaries generally follow visible, physical features, and county boundaries. The CSAC's may use MCD and incorporated place boundaries as census tract/BNA boundaries in New Jersey, New York, Pennsylvania, and the New England States because the boundaries tend to be stable and locally known. In a few rare instances, a census tract or BNA may consist of discontiguous areas. These discontiguous areas may occur where the census tracts are coextensive with all or parts of legal entities that are themselves discontiguous. Any updates and corrections to county boundaries following the assignment of block numbers in 1988 resulted in the creation of new census tracts/BNA's because Census Tracts/BNA's must nest within a county, and the existing 1990 census tracts were in place for the 1990 census and could not be shifted. At the request of some local CSAC's, the Census Bureau also has resolved a number of census tract boundary discrepancies. The Census Bureau identified the revised census tracts/BNA's with a unique suffix ranging from .70 to .98 (e.g., 1234.98), so that the data users can easily determine which census tracts/BNA's are affected. The Census Bureau made these changes after the release of the TIGER/Line(TM) Precensus Files, 1990. The census tract boundaries follow legal county boundaries as of January 1, 1990. Relationship to Other Geographic Entities - - The census tracts and BNA's represent the same level of geography and share the same field in the TIGER/Line(TM) files. Census tracts or BNA's entirely cover a county. A county contains either census tracts or BNA's, but not a combination of both. Census BG's and blocks are uniquely numbered within census tracts and BNA's. Record Locations: Census Tract/BNA Codes RT Field Name Description 1 CTBNAL Basic number and suffix (left side of complete chain) 1 CTBNAR Basic number and suffix (right side of complete chain) 3 CTBNA80L 1980 basic no. and suffix (left side of complete chain) 3 CTBNA80R 1980 basic no. and suffix (right side of complete chain) A CTBNA Basic number and suffix (polygon) F CTBNA90 Basic number and suffix for a polygon with corrected 1990 code(s) Codes: Census Tracts/BNAs Basic number range for census tracts: "0001" to "9499" Basic number range for BNA's: "9500" to "9989" Default basic number range for census tracts/BNA's "0000" Note: All polygons have a non-blank census tract/BNA basic number. The left and right side complete chain tract/BNA numbers are not blank except where they are located along the outside edge of the county boundary. The TIGER/Line(TM) files do not contain geographic codes for the area outside of the county file. The TIGER/Line(TM) files identify boundary complete chains by placing a "1" in the single-side segment field in Record Type 1. The Census Bureau assigned a default census tract/BNA number "0000" in some coastal and Great Lakes waters rather than extend the census tract/BNA boundary into the Great Lakes or out to the three-mile limit. The Census Bureau closed some census tract/BNA boundaries along the shoreline or just offshore, and assigned the default census tract/BNA and special block numbers to the offshore areas. Suffix: Suffix codes for census tracts: "01" to "99" Suffix codes for BNA's: "85" to "99" Suffix code for census tracts and BNA's without a suffix: " " Suffix code for crews-of-vessels census tracts/BNA's (see the section on crews-of-vessels for explanation): "99" Counties and Statistically Equivalent Entities Identification The first-order divisions of each State are counties for 48 States, parishes for Louisiana, and boroughs and census areas for Alaska. In addition, the Census Bureau treats the following entities as equivalents of counties for purposes of data presentation: independent cities in Maryland, Missouri, Nevada, and Virginia; the portion of Yellowstone National Park in Montana; "District of Columbia" for the District of Columbia; municipios in Puerto Rico; and a variety of entities in the outlying areas. The TIGER/Line(TM) files contain several 3-numeric character fields identifying the FIPS county code for the 1980 and 1990 censuses and the FIPS county codes for corrected and current entities. The TIGER/Line(TM) files use some State and county code fields to identify specific TIGER/ Line(TM) files. Record Locations: County and County Equivalents Codes RT Field Name Description 1 COUNTYL FIPS code (left side of complete chain) 1 COUNTYR FIPS code (right side of complete chain) 3 COUN80L FIPS code for 1980 (left side of complete chain) 3 COUN80R FIPS code for 1980 (right side of complete chain) 5 COUNTY FIPS code for file identification (complete chain) 7 COUNTY FIPS code for file identification (polygon) 8 COUNTY FIPS code for file identification (polygon) A COUNTY FIPS code for file identification (polygon) F COUNTY FIPS code for file identification (polygon) F COUNTY90 FIPS code for a polygon with corrected 1990 code(s) G COUNTY FIPS code for file identification (polygon) G COUNTYCU FIPS code for a polygon with updated code(s) from boundary changes since January 1, 1990 I COUNTY FIPS code for file identification (polygon) P COUNTY FIPS code for file identification (polygon) R COUNTY FIPS code for file identification (polygon) Codes: County and County Equivalents See Appendix A for a list of FIPS county and county- equivalent codes by State and State-equivalent entity. Note: All polygons have a non-blank county code. The left- and right-side county codes on complete chains are not blank except where they are located along the outside edge of the county boundary feature. The TIGER/Line(TM) files do not contain geographic codes for the area outside the county file. The TIGER/Line(TM) files identify boundary complete chains by placing a "1" in the single- side segment field in Record Type 1. County Subdivisions (MCD's, Census County Division [CCD's], and Unorganized Territories [UT's]) Identification The TIGER/Line(TM) files contain both 3-numeric character census code fields and the 5-numeric character FIPS code fields for county subdivisions. The TIGER/Line(TM) files use a single set of fields to identify the two types of county subdivisions. Legal Entities * MCD's are legally defined subcounty areas such as towns (in eight States) and townships. For the 1990 census, these occur in 28 States, Puerto Rico, and the Outlying Areas. * Some States have incorporated places that are not part of any MCD. These places also serve as primary legal subdivisions and have a unique census MCD code in addition to the census place code. The TIGER/Line(TM) files will show the same FIPS PUB 55-3 code in the FIPS county subdivision code field and the FIPS place code field. * In New York and Maine, AIR's exist outside the jurisdiction of any town (MCD) and thus also serve as MCD-equivalent entities. Statistical Entities * CCD's are areas delineated by State officials and the local CSAC's for statistical purposes. CCD's exist where: 1. There are no legally established MCD's; 2. The MCD's do not have governmental or administrative purposes; 3. The boundaries of the MCD's change frequently; and/or 4. The MCD's are not generally known to the public. CCD boundaries usually follow visible features and in most cases, coincide with census tract or BNA boundaries. CCD's have been established for the following 21 States: Alabama Nevada# Arizona New Mexico California Oklahoma Colorado Oregon Delaware South Carolina Florida Tennessee Georgia Texas Hawaii Utah Idaho Washington Kentucky Wyoming Montana # For the 1980 census, the county subdivisions recognized for Nevada were MCD's. * Census Subareas - - These are subdivisions of boroughs and census areas, the county equivalent entities in Alaska. The State of Alaska and the Census Bureau cooperatively delineated the census subareas to serve as the statistical equivalents of MCD's. * UT's - - For States with partial MCD coverage, the Census Bureau assigns one or more UT codes to the non- MCD area. UT's have county subdivision codes and names that are identified in the TIGER/GICS data product. Nine States have UT's for the 1990 census: Arkansas Minnesota Iowa North Carolina Kansas# North Dakota Louisiana South Dakota Maine Indiana# # For Record Types F and G, Indiana has UT's and Kansas no longer has UT's. Record Locations: County Subdivision Codes RT Field Name Description 1 FMCDL Code (left side of complete chain) 1 FMCDR FIPS PUB 55-3 code (right side complete chain) 3 FMCD80L FIPS PUB 55-3 code 1980 (left side of complete chain) 3 FMCD80R FIPS PUB 55-3 code 1980 (right side of complete chain) 3 MCD80L 1980 census code (left side of complete chain) 3 MCD80R 1980 census code (right side of complete chain) 3 MCDL 1990 census code (left side of complete chain) 3 MCDR 1990 census code (right side of complete chain) A FMCD FIPS PUB 55-3 code (polygon) F FMCD90 FIPS code for a polygon with corrected 1990 code(s) G FMCDCU FIPS code for a polygon with updated code(s) from boundary changes since January 1, 1990 Codes: County Subdivisions Please refer to the PUBGRF, FIPS PUB 55-3, or the Census Bureau's TIGER/GICS for a list of valid codes and entity names. Note: All polygons have a non-blank county subdivision code. The left-and right-side MCD/CCD numbers are not blank except where they are located along the outside edge of the county boundary feature. The TIGER/Line(TM) files do not contain geographic codes for the area outside of the county file. The TIGER/Line(TM) files identify boundary complete chains by placing a "1" in the single-side segment field in Record Type 1. The Census Bureau assigned a default MCD number "000" in some coastal and Great Lakes waters where MCD's do not extend into the Great Lakes or out to the three-mile limit. Similarly, the Census Bureau closed some census tract/BNA boundaries along the shoreline or just offshore, and assigned the default census tract/BNA and special block numbers to the offshore areas. Congressional District Identification The TIGER/Line(TM) files contain 2-character numeric code fields for the 101st and 103rd Congressional districts. Congressional districts are numbered uniquely within State. Record Locations: Congressional Districts RT Field Name Description A CD101 101st Congress (polygon) A CD103 103rd Congress (polygon) Codes: Congressional Districts Congressional district codes -- 101st Congress: "01" to "45" Congressional district codes -- 103rd Congress: "01" to "52" "At large": "00" Nonvoting delegate: "98" No representation in Congress: "99" Note: The congressional district field always has a value other than blank for all polygons. Crews-of-Vessels Identification Crews-of-vessels represent the population on military (including Coast Guard) and/or merchant ships; it does not include the inhabitants of houseboats or marinas. The census population tables show the vessels population in a unique census tract/BNA and census block. A crews-of- vessels census tract/BNA and block appear on census maps as an anchor symbol with its census tract/BNA and block numbers, rather than as a delimited area. Crews-of-vessels census tract/BNA numbers use the same basic census tract/BNA number as the nearby land census tract/BNA with which the vessel(s) is associated, plus a suffix of "99," shown in decimal notation; for example, census tract 1234.99. Crews-of-vessels block numbers use the same basic block number as the associated land block in that census tract/BNA, plus a block suffix of "Z;" for example, block 901Z in census tract 1234.99. In such a situation, the related land block also receives a suffix, even though it may not be split by a boundary; for example, the addition of a crews-of-vessels associated with block 901 creates blocks 901A and 901Z. The Census Bureau will not use the "Z" census block suffix for any purpose other than crews-of-vessels. Either the left or right census tract/BNA and census block identified in Record Type 1 will indicate the location where the population is assigned. The census tract/BNA and census block for the crews-of-vessels is infinitesimally small requiring only one complete chain with a start node equal to the end node and two of shape points so that the polygon appears as a minute triangle. The coordinates on Record Type 1 and Record Type 2 will place the census block on the shore inside the land block with the same 3-digit collection block number, not in the water as shown on the census maps. The area measurement enclosed by the special crews-of-vessels census tract/BNA and block is defined as zero. On a census map sheet, an anchor symbol appears in the water accompanied by the census tract/BNA number and the Z- suffixed block number. The location of the anchor symbol is arbitrary and reflects neither the location of the vessel(s) at the time of the census nor the crews-of- vessels census tract/BNA and block as it appears in the TIGER/Line(TM) file. Record Locations: Crews-of-Vessels The crews-of-vessels entities are identified by unique census tract/BNA codes and block number suffixes. See the sections on census tracts and census blocks for record locations and field names. Codes: Crews-of-Vessels Census tract/BNA suffix: "99" Block number suffix: "Z" Places Identification The TIGER/Line(TM) files use a single set of fields to identify places that are legal entities and places that are statistical entities: Legal Entities * Incorporated Places are legal entities incorporated under individual State law. An incorporated place can be a legal city, town, borough, or village. Incorporated places exclude: 1. The boroughs in Alaska, which are treated as county equivalents; 2. Towns in the New England States, New York, and Wisconsin, which are treated as MCD's; and 3. The boroughs of New York which are treated as MCD's. * A consolidated city exists where an incorporated place has consolidated its government with the larger county or MCD and one or more separately incorporated places. The incorporated place(s) and the county or MCD continue to exist as legal entities even though they are included in the consolidated city government. The primary incorporated place is referred to as a "consolidated city." The TIGER/Line(TM) files do not contain codes for consolidated cities. In order to use TIGER/Line(TM) data for consolidated cities, the data user must assign a code to all coextensive entities or aggregate places. Statistical Entities * CDP's -- CDP's are recognizable communities or concentrations of population that are not incorporated places. CDP's may have a locally recognized name, but do not have legally defined corporate limits or corporate powers. The Census Bureau defines CDP's in cooperation with State officials, AIR officials, and local data users for data presentation. Places may extend across county and county subdivision boundaries. The census and FIPS place codes uniquely identify a place within a State. Note that legally incorporated places and CDP's are mutually exclusive and are identified in the same TIGER/Line(TM) field. Dependent and Independent Places -- Depending on the State, incorporated places are either dependent within or independent of county subdivisions, or have a mixture of dependent or independent places. Dependent places are part of the county subdivision; the place's county subdivision code is the same as the underlying county subdivision(s). Independent places are separate from the adjoining county subdivisions and have their own county subdivision code (or codes if the place lies in multiple counties). These places also serve as primary county subdivisions and have a unique Census MCD code in addition to the Census place code. The TIGER/Line(TM) files will show the same FIPS PUB 55-3 code in the FIPS county subdivision code field and the FIPS place code field. CDP's always are dependent within county subdivisions. Corporate Corridors and Offset Corporate Boundaries -- A corporate corridor is a narrow, linear part of an incorporated place. The corporate corridor includes the street and/or right-of-way or a portion of the street and/or right-of-way within the incorporated place. It excludes from the incorporated place those structures, such as houses, apartments, or businesses, that front along the street or road; see Figure 4-4. A corporate limit offset boundary exists where the incorporated place lies on only one side of the street and includes all or part of the street and/or the right-of-way. It does not include the houses or land that adjoin the side of the street with the corporate limit offset boundary. It is possible to have two or more corporate limit offset boundaries in the same street or right-of-way. In order to reduce the overprinting of symbols on the printed or plotted census maps, a corporate corridor is shown by only one symbol along its center line rather than by a symbol that follows its outer boundary. Corporate offset limit boundaries use the same map symbology as non- offset boundaries. Figure 4-4 shows the place level mapping symbols for corporate corridors and corporate offset limits. To facilitate address coding, the street name and address ranges are generally duplicated on complete chains with a CFCC of F11 (nonvisible offset boundary) or F12 (nonvisible corporate corridor). The duplicate street names for the F11 and F12 features are on Record Type 5 and the duplicate address ranges are on Record Type 6. However, Record Type 1 will not indicate that the street or right-of-way lies within a corporate corridor or offset boundary and that the address ranges lie outside the corporate corridor or offset boundary and are encoded on either side of these lines. When data users find duplicate address ranges where one of the duplicates is on a complete chain with a CFCC of F11 or F12, use this address range for address geocoding rather than the range on the street feature with a CFCC beginning with "A" (see Figure 4-5). Likewise, use the street name and address ranges on the related street feature (CFCC beginning with "A") for mapping or vehicle routing. Field Size -- Places are represented in the TIGER/Line(TM) files by either a 5-numeric character FIPS code or a 4- numeric character census code. Record Locations: Incorporated Place/CDP Codes RT Field Name Description 1 FPLL FIPS PUB 55-3 code (left side of complete chain) 1 FPLR FIPS PUB 55-3 code (right side of complete chain) 3 FPL80L 1980 FIPS PUB 55-3 code (left side of complete chain) 3 FPL80R 1980 FIPS PUB 55-3 code (right side of complete chain) 3 PL80L 1980 census code (left side of complete chain) 3 PL80R 1980 census code (right side of complete chain) 3 PLL 1990 census code (left side of complete chain) 3 PLR 1990 census code (right side of complete chain) A FPL FIPS PUB 55-3 code (polygon) F FPL90 FIPS PUB 55-3 code for a polygon with corrected 1990 code(s) G FPLCU FIPS PUB 55-3 code for a polygon with updated code(s) from boundary changes since January 1, 1990 Codes: Incorporated Places/CDP's Please refer to the TIGER/Line(TM) Geographic Names files, FIPS PUB 55-3, or the Census Bureau's TIGER/GICS product for a list of valid codes and entity names. Note: The data field is blank where there are no places. School Districts Identification The Census Bureau is releasing the school district codes in the 1992 TIGER/Line files as part of the National School District Program sponsored by the U.S. Department of Education, National Center for Education Statistics. This program was designed to provide 1990 census data tabulations for school districts. The program identifies three possible levels of school districts representing different segments of the school-age population (elementary, intermediate, and secondary) and a "unified" category to identify those school districts that represent all grade levels. The elementary, intermediate, and secondary levels of school district can overlap another because they represent different segments of the school-age population; for example, an intermediate school district could cover parts of several elementary school districts. The 1992 TIGER/Line files use separate fields to accommodate for the overlap. The 1992 TIGER/Line files may not contain a code for all grade levels. The 1992 TIGER/Line files contain a "unified" school district code for those school districts where all levels are represented in a single district. The elementary, intermediate, and secondary school district code fields are blank if there is a unified school district code. Exceptions exist for the State of Hawaii and the five New York City Boroughs; New York City and Hawaii are each single school districts. The National School District Program has mapped Attendance Zones for each school in these two districts. School districts may cut through existing census blocks. In such instances, the Census Bureau created new complete chains and GT-polygons. However, the school district boundaries did not create new blocks. The tabulation blocks may contain more than one polygon, and each polygon may have a different school district code. The block parts/polygons allocated to the different school districts do not have separate tabulation block numbers. The 1992 TIGER/Line files store the school district codes in a set of four 5-character fields. All codes consist of numeric characters. Record Locations: School District Codes RT Field Name Description A SDELM Elementary school district code (polygon) A SDMID Middle school district code (polygon) A SDSEC Secondary school district code (polygon) A SDUNI Unified school district code (polygon) Codes: School Districts The U.S. Department of Education's Common Core Data File contains the school district names associated with the codes. For information about the relationship between the school district codes and their names, contact: Lee Hoffman Chief, General Survey and Analysis Branch Rm. 410F National Center for Education Statistics 555 New Jersey Ave., NW Washington, DC 20208 Phone: (202) 219-1621 Unified and elementary, intermediate, and secondary school districts may have blank values (see discussion above). It is possible that an area may have a blank code for some grade level school districts. Note that "99999" is a pseudo school district code assigned to non-water blocks for which the National School District Program does not report a school district. Some large water areas have a pseudo school district code of "99998." States and Statistically Equivalent Entities Identification In addition to the 50 States, the Census Bureau treats the District of Columbia, Puerto Rico, and each of the outlying areas (American Samoa, Guam, the Northern Mariana Islands, Palau, and the Virgin Islands of the United States) as the statistical equivalent of a State for the purpose of data presentation. The Census Bureau also produces TIGER/Line(TM) files for the Midway Islands. The Census Bureau generated the 1990 Census TIGER/Line file for the Marshall Islands and the Federated States of Micronesia, but these areas are excluded from the version 5 release. Record Locations: State Codes RT Field Name Description 1 STATEL FIPS code (left side of complete chain) 1 STATER FIPS code (right side complete chain) 3 STATE80L FIPS code for 1980 (left side of complete chain) 3 STATE80R FIPS code for 1980 (right side of complete chain) 5 STATE FIPS code for file identification (complete chain) 7 STATE FIPS code for file identification (polygon) 8 STATE FIPS code for file identification (polygon) A STATE FIPS code for file identification (polygon) F STATE FIPS code for file identification (polygon) F STATE90 FIPS code for a polygon with corrected 1990 code(s) G STATE FIPS code for file identification (polygon) G STATECU FIPS code for a polygon with updated code(s) from boundary changes since January 1, 1990 I STATE FIPS code for file identification (polygon) P STATE FIPS code for file identification (polygon) R STATE FIPS code for file identification (polygon) Codes: States Please refer to Appendix A for a list of FIPS State codes. Note: All polygons have a non-blank 2-character numeric State code. The State codes for the left-and right-side of a complete chain are not blank except where they are located along the outside edge of the county boundary feature; the TIGER/Line(TM) files do not contain geographic codes for the area outside of the county file. The TIGER/Line(TM) files identify boundary complete chains by a "1" in the single-side segment field in Record Type 1. Sub-MCD's Identification Legally defined subdivisions of a MCD used for subbarrios in Puerto Rico and municipal districts in the Federated States of Micronesia. The TIGER/Line(TM) files contain both the 2-numeric character census and the 5-numeric character FIPS codes. Record Locations: Sub-MCD Codes RT Field Name Description 1 FSMCDL FIPS PUB 55-3 code (left side of complete chain) 1 FSMCDR FIPS PUB 55-3 code (right side of complete chain) 3 SMCDL 1990 census code (left side of complete chain) 3 SMCDR 1990 census code (right side of complete chain) F FSMCD90 FIPS PUB 55-3 code for a polygon with corrected 1990 code(s) G FSMCDCU FIPS PUB 55-3 code for a polygon with updated code(s) from boundary changes since January 1, 1990 Codes: Sub-MCD's Please refer to the TIGER/Line(TM) Geographic Names files, FIPS PUB 55-3, or the Census Bureau's TIGER/GICS product for a list of valid codes and entity names. Note: The data field is blank if there is no sub-MCD. Traffic Analysis Zone (TAZ) Identification Many metropolitan planning organizations established TAZ's for use in tabulating 1990 census data for the Census Transportation Planning Package. The TAZ's are established outside the Census Bureau and do not appear in the Census TIGER data base. The Census Bureau will not show them in any 1990 Census TIGER extract, but the Census Bureau may add them to the Census TIGER data base and extracts at a later time. Record Locations: TAZ Codes RT Field Name Description A TAZ Code (polygon) Codes: TAZ's No data is currently available for TAZ's; all records contain a blank TAZ field. Urbanized Areas (UA's) Identification A UA comprises a place and the adjacent densely-settled surrounding territory that together have a minimum population of 50,000 people. The densely-settled surrounding territory generally consists of an area with continuous residential development and an overall population density of at least 1,000 people per square mile. The TIGER/Line(TM) files identify UA's with a 4- character numeric code field. All polygons that have a UA code (other than blank) will have a U/R flag equal "U." See the discussion on U/R flags. Record Locations: UA Codes RT Field Name Description A UA 1990 census UA code (polygon) Codes: UA's The UA code is a 4-character numeric census code. The names associated with the code appear in the TIGER/GICS product. Appendix G lists the UA names and codes. Urban/Rural Designation (U/R) Identification The TIGER/Line(TM) files include a 1-character U/R flag: "R" Rural, not urban "U" Urban, in a UA or an urban place The Census Bureau defines "urban" for the 1990 census as comprising all territory and population in UA's and in places of 2,500 or more people located outside of the UA's. The Census Bureau also distinguishes the urban and rural population, within incorporated places whose boundaries contain large, sparsely populated--or even unpopulated-- area. These "extended cities" have either 25 percent of their land area or at least 25 square miles classified as "sparsely-settled." The sparsely-settled area must consist of at least one group of one or more contiguous census blocks. Each group must be at least 5 square miles in area and have an overall population density of less than 100 people per square mile. Polygons in the group of sparsely- settled blocks will have a flag equal to "R;" the densely- populated blocks will have a flag equal to "U." Incorporated places (based on 1990 census boundaries) with both urban and rural flagged polygons are extended cities. For the 1990 census, 280 incorporated places were defined as extended cities. Extended cities exist both inside and outside of UA's. The Census Bureau assigns the U/R flag to tabulation blocks, so all GT-polygons within a block have the same U/R flag. All blocks that have a UA code (other than blank) will have an U/R flag equal "U." Blocks in places that qualify as urban places, but not in a UA, do not have a UA code, but do have a U/R flag equal to "U." Rural areas are identified by a "R" flag and will not have a UA code. Record Locations: U/R Flags RT Field Name Description A URBFLAG 1990 census U/R flag (polygon) Codes: U/R Flags Urban: "U" Rural: "R" Voting Districts (VTD's) Identification For the 1990 census, the term "VTD" replaces the 1980 census term "election precinct." A VTD is any of a variety of areas (for example, election districts, precincts, legislative districts, and wards) defined by State and local governments for purposes of elections. The 1990 VTD codes that appear in the TIGER/Line(TM) files were supplied by the State governments in response to the requirements of the 1990 Census Redistricting Data Program. The boundaries of the VTD's recorded in the TIGER/Line(TM) files may represent "pseudo-VTD's." The States may have relocated the boundaries of the actual VTDs to a nearby block boundary because they were required to submit VTD's that follow 1990 census block boundaries. The pseudo-VTD's are identified in the TIGER/Line(TM) Geographic Names files. States had the option of participating in the program on a county-by-county or even a partial county basis. The VTD's do not appear in all or throughout some TIGER/Line(TM) files. The following States did not participate in the VTD program: Kentucky Montana Mississippi Oregon The following States have partial VTD coverage: Alabama VTD's for 59 of the 67 counties Georgia VTD's for 158 of the 159 counties Idaho VTD's for 32 of the 44 counties North Carolina VTD's for 48 of the 100 counties Ohio VTD's for 55 of the 88 counties South Dakota VTD's for 65 of the 66 counties Texas VTD's for 87 of the 254 counties Wisconsin VTD's for 70 of the 72 counties The VTDs are represented by a 4-character alphanumeric code. Descriptions of the codes appear in the TIGER/Line(TM) Geographic Names files. Record Locations: VTD Codes RT Field Name Description 3 VTDL Code (left side of complete chain) 3 VTDR Code (right side of complete chain) Codes: VTD's A VTD code consists of any non-zero combination of numbers and alphabetic characters. Note: A VTD code equal to "ZZZZ" is used to designate coastal water areas excluded from the VTD's. Some States did extend VTD coverage into water areas. Blank space indicates that VTD coverage is not available for a whole county.