1980 Block Boundaries

NHGIS has released Version 2.0 of our 1980 block shapefiles, depicting 1980 census block boundaries in 62 metropolitan areas throughout the U.S. We will update and extend the shapefiles in future releases as we complete block editing work for more areas.

These files provide a more accurate and complete representation of 1980 block boundaries than is available from the U.S. Census Bureau's 1992 TIGER/Line Files, the only previously existing source of nationwide digital 1980 block definitions.

We currently provide the boundary files through this web page along with documentation and census summary statistics for 1980 blocks. In the future, we will provide both the boundary files and summary tables through the NHGIS Data Finder.

Overview

The U.S. Census Bureau's 1992 TIGER/Line Files include both 1990 and 1980 census block boundaries, but the 1980 blocks are badly incomplete and often inaccurate. Of the 2.5 million blocks that appear in the 1980 census summary tables, about 765,000 do not appear in the 1992 TIGER/Line Files, and there are missing cases in nearly every county where block data were provided.

Using the 1980 paper census block maps as a guide, NHGIS staff are manually editing data from the 1992 TIGER/Line Files to recover as many missing blocks as possible. The Census Bureau published the paper maps separately by Standard Metropolitan Statistical Area (SMSA), so NHGIS editing work is also organized by SMSA.

Initial versions of our 1980 block shapefiles will cover only the SMSAs that we have completed. We plan to release more versions including more SMSAs at regular intervals until the project has ended.

NHGIS validates the edited geographic block data against the statistical block data from 1980 Summary Tape File 1 (STF1). For a small portion of the blocks that appear in STF1, we are unable to find corresponding blocks on the paper maps or in the TIGER/Line data, so we cannot provide complete block definitions for all reported statistics. Our validation process produces summaries of the discrepancies between the edited boundary data and statistical data. We supply these summaries for user reference along with the shapefiles.

We also provide separate files of block-level summary tables derived from the 1980 STF1 dataset. This is important because the original STF1 includes data only for block parts and not for the whole collection blocks that the boundary files depict.

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Technical Details

Basics

  • The boundary data are stored in shapefiles within ZIP archives
  • There is a separate shapefile for each state (or state equivalent) where boundaries are currently available
  • There is a nationwide shapefile that includes all block boundaries available at this time
  • Two supplemental CSV (comma-separated-values) files accompany each shapefile within the ZIP archives
    • data_missing_polygon - Lists blocks that have records in the statistical tables but do not have polygons in the shapefile
    • polygon_missing_data - Lists blocks that have polygons in the shapefile but do not have records in the statistical tables
  • The statistical and boundary files include standard NHGIS GISJOIN identifiers
  • The statistical table data are stored in a CSV file within a ZIP archive
  • There are two nationwide CSV files
    • One includes all tables
    • One includes a collection of popular tables
  • There is a CSV file for each state (or state equivalent) with boundaries currently available
  • All ZIP archives include human-readable codebooks describing the contents of the data files

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Geographic Coverage

We plan to produce 1980 block shapefiles for all of the Standard Metropolitan Statistical Area (SMSAs) that are covered (imperfectly) in the 1992 TIGER/Line Files. In 1980, the Census Bureau's block data program covered only urbanized areas and large incorporated places (those with 10,000 or more residents based on pre-1980 sources). State and local agencies also contracted with the Bureau to obtain block data for many additional areas, but the 1992 TIGER/Line Files provide very limited information for the blocks in these areas, so we do not expect to complete those.

The 1980 block shapefiles are organized by state for consistency with NHGIS block boundary files for later years. A given state's shapefile includes blocks only for SMSAs that NHGIS has completed within that state. To obtain all block boundaries for an SMSA that crosses state boundaries, a user will need to combine block files from each corresponding state.

Future versions of the shapefiles will extend coverage within currently included states and add new files for other states. Our work was initially limited to a small set of SMSAs for which we could obtain block maps. We have now found lending sources for nearly all SMSAs, so we have recently begun to prioritize the largest SMSAs.

We detail current coverage by state and by SMSA in this spreadsheet:

Click below for a list of currently covered SMSAs ordered by population:

Covered Metro Areas by Population

Rank Standard Metropolitan Statistical Area 1980 Population
1. New York, N.Y.-N.J. 9,120,346
2. Los Angeles-Long Beach, Calif. 7,477,503
3. Chicago, III. 7,103,624
4. Philadelphia, Pa.-N.J. 4,716,818
6. San Francisco-Oakland, Calif. 3,250,630
14. Baltimore, Md. 2,174,023
15. Minneapolis-St. Paul, Minn.-Wis. 2,113,533
16. Atlanta, Ga. 2,029,710
19. Cleveland, Ohio 1,898,825
20. San Diego, Calif. 1,861,846
22. Denver-Boulder, Colo. 1,620,902
23. Seattle-Everett, Wash. 1,607,469
26. Phoenix, Ariz. 1,509,052
27. Cincinnati, Ohio-Ky.-Ind. 1,401,491
28. Milwaukee, Wis. 1,397,143
29. Kansas City, Mo.-Kans. 1,327,106
34. Indianapolis, Ind. 1,166,575
35. Columbus, Ohio 1,093,316
42. Memphis, Tenn.-Ark.-Miss. 913,472
44. Nashville-Davidson, Tenn. 850,505
45. Birmingham, Ala. 847,487
51. Toledo, Ohio-Mich. 791,599
52. Honolulu, Hawaii 762,565
59. Gary-Hammond-East Chicago, Ind. 642,781
65. New Brunswick-Perth Amboy-Sayreville, N.J. 595,893
67. Omaha, Nebr.-lowa 569,614
69. Jersey City, N.J. 556,972
70. Austin, Tex. 536,688
76. Wilmington, Del.-N.J.-Md. 523,221
78. Fresno, Calif. 514,621
80. Baton Rouge, La. 494,151
82. El Paso, Tex. 479,899
85. Las Vegas, Nev. 463,087
115. Madison, Wis. 323,545
130. Salinas-Seaside-Monterey, Calf. 290,444
138. Eugene-Springfield, Oreg. 275,226
149. Daytona Beach, Fla. 258,762
164. Killeen-Temple, Tex. 214,656
170. Sarasota, Fla. 202,251
174. Reno, Nev. 193,623
175. Lincoln, Nebr. 192,884
183. Springfield, Ohio 183,885
184. Portland, Maine 183,625
190. Green Bay, Wis. 175,280
194. Boise City, Idaho 173,036
200. St. Cloud, Minn. 163,256
228. Waterloo-Cedar Falls, Iowa 137,961
253. Kenosha, Wis. 123,137
255. Lafayette-West Lafayette, Ind. 121,702
262. Sioux City, lowa-Nebr. 117,457
266. Burlington, Vt. 114,070
278. Sioux Falls, S. Dak. 109,435
283. Kokomo, Ind. 103,715
288. Grand Forks, N.Dak.-Minn. 100,944
294. Bloomington, Ind. 98,785
300. Rochester, Minn. 92,006
301. La Crosse, Wis. 91,056
307. Bangor, Maine 83,919
309. Iowa City, Iowa 81,717
310. Great Falls, Mont. 80,696
311. Bismarck, N. Dak. 79,988
313. Lewiston-Auburn, Maine 72,378


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Data for Whole Collection Blocks, Not Tabulation Blocks

The Census Bureau defines two types of census blocks: collection blocks and tabulation blocks. As implied by these names, the Census Bureau generally tabulates and publishes data only for tabulation blocks, not collection blocks. The collection blocks are defined first, before census operations, and their boundaries mainly follow observable physical features like roads, railroads, streams, shorelines, etc. Most tabulation blocks match collection blocks, but tabulation blocks can include additional subdivisions wherever collection blocks are split by higher-level reporting areas, such as incorporated places and minor civil divisions (MCDs). As explained in the Census Bureau's Geographic Areas Reference Manual (p. 11-14), "This methodology permits the Census Bureau to accommodate changes to the boundaries of legally recognized entities as they occur and still maintain a stable inventory of collection blocks."

In 1980 block data and on 1980 block maps, the block identifiers correspond only to collection blocks and do not distinguish the parts of collection blocks (i.e., the tabulation blocks) that lie in different places or MCDs. The Census Bureau revised this practice in 1990, adding suffixes to tabulation block codes to distinguish each part of a split collection block. As a result, every census reporting area at every census summary level now corresponds exactly to a set of uniquely identified tabulation blocks, but that is not the case in 1980 data.

Example of a Block Split by a Place Boundary with Summary Data for the Split Block Parts and the Corresponding Whole Block

Figure 1. Two STF1 block data records have the same tract and block identifiers but unique place identifiers. We generate new data for the whole collection block with a population equal to the sum of the two split parts' populations.

In the original block-level statistical data in 1980 STF1, there are separate records for each part of a split collection block, each with unique statistics, but without a unique tabulation block identifier. A user must examine the place or MCD codes to determine which part of the collection block each record corresponds to. Unfortunately, there are discrepancies between the place and MCD identifiers in the statistical data and the place and MCD boundaries in TIGER/Line Files and on the paper maps, preventing us from exactly matching the block boundary data to the original tabulation blocks.

To resolve these discrepancies, NHGIS provides boundary data for whole 1980 collection blocks only, and we derive new statistical data for the whole blocks.

The statistical data files include all collection blocks identified in 1980 STF1, including areas not yet covered in the NHGIS boundary files. Out of the 2.5 million blocks identified in 1980 STF1, only about 61,000 are split by place or MCD boundaries. Of these blocks, only 35,000 (those that had non-zero counts for two or more of their parts) required data aggregation.

We derived new data for all tables in the NHGIS dataset "1980 Census: STF1 - 100% Data". That dataset currently provides block data at two geographic levels, which separately cover states with strong MCDs and those without:

  • MCD States: State--Standard Metropolitan Statistical Area--County--County Subdivision--Place--Census Tract--Block
  • Non-MCD States: State--Standard Metropolitan Statistical Area--County--Place--Census Tract--Block

To aggregate the data, we first sum the counts for all records that share the same codes for state--county--census tract--block. Then for tables that report median values rather than counts, where aggregation is necessary, we use the same method that the the Census Bureau used, interpolating median estimates from the associated binned count data. For instance, to interpolate an estimate for median age, we use the aggregated counts of persons age 0-4, 5-9, and so on. We provide complete details on this methodology in the codebooks that accompany the data files.

The aggregated collection block data are therefore provided at the following geographic level for all states:

  • State--County--Census Tract--Block

A more detailed explanation of the aggregation process and variable definitions is available in the codebook that accompanies the data file.

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For user convenience, the tables most requested by NHGIS users are available in a separate CSV file. This file contains 16 of the 82 tables in 1980 Summary Tape File 1. A full description of these tables is available in the codebook, which is included with the data file in the download ZIP file. Click below for an overview of the tables.

  Table Name Description
1. Persons Population count
2. Urban/Rural Status Urbanized area, outside urbanized area, and rural population counts
3. Households Count of households
4. Housing Units Count of housing units
5. Occupancy Status Counts of occupied and vacant year-round housing units
6. Race Population count by race
7. Spanish Origin Population count by Spanish origin
8. Persons of Spanish Origin Count of persons of Spanish origin
9. Race [Persons of Spanish Origin] Count of persons of Spanish origin by Race
10. Age Population count by age
11. Tenure Counts of owner-occupied and renter occupied housing units
12. Tenure by Race of Householder Counts of owner-occupied and renter occupied housing units by race of householder
13. Value Counts of specified owner-occupied housing units by value
14. Median Value Median value of specified owner-occupied housing units
15. Contract Rent Counts of specified renter occupied housing units by contract rent
16. Median Contract Rent Median contract rent for specified renter-occupied housing units paying cash rent


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Download: Boundaries

The 1980 block boundaries are available as statewide or nationwide shapefiles.

The nationwide file includes boundaries for all covered metro areas, as listed here:

 

1980 Census Block Boundary Data by State
Alabama Kansas New York
Arizona Kentucky North Dakota
Arkansas Louisiana Ohio
California Maine Oregon
Colorado Maryland Pennsylvania
Delaware Michigan South Dakota
Florida Minnesota Tennessee
Georgia Mississippi Texas
Hawaii Missouri Vermont
Idaho Montana Washington
Illinois Nebraska Wisconsin
Indiana Nevada  
Iowa New Jersey  


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Download: Statistics

Summary statistics for whole collection blocks, derived from 1980 STF1, are available as statewide or nationwide comma-separated values (CSV) files.

 

1980 Census Block Statistical Data by State
Alabama Kansas New York
Arizona Kentucky North Dakota
Arkansas Louisiana Ohio
California Maine Oregon
Colorado Maryland Pennsylvania
Delaware Michigan South Dakota
Florida Minnesota Tennessee
Georgia Mississippi Texas
Hawaii Missouri Vermont
Idaho Montana Washington
Illinois Nebraska Wisconsin
Indiana Nevada  
Iowa New Jersey  


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Feedback and Questions

You may direct any comments or questions about these files to nhgis@umn.edu.

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Citation and Use

Use of the NHGIS 1980 Block Boundary Files is subject to the same conditions as for all NHGIS data. See Citation and Use of NHGIS Data.

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Credits

Our production of 1980 Block Boundary Files is supported by funding from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) (R01HD057929).

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