Documentation for the digital sources of NHGIS data tables:
- Secondary Sources (1790-2010)
- 1790-1960
- 1910, 1920 & 1930 Tract & Enumeration District Data
- 1915-1972 Vital Statistics: Natality & Mortality Data
- 1970-2007 Vital Statistics: Natality & Mortality Data
- 1867-2010 Vital Statistics: Marriage & Divorce Data
- 1920-1935 Census of Agriculture Data
- 1920-1936 Bank Deposit Data
- 1940, 1950 & 1960 Tract Data
- Decennial Census Summary Files (1960-2020)
- County Business Patterns (1970-2003)
- American Community Survey (2009-2023)
See also the Overview of NHGIS Datasets for summaries of the sources used.
Secondary Sources
Most NHGIS data tables for years prior to 1970 were originally entered into machine-readable digital formats from print publications by researchers at other institutions.
The documentation provided here describes the content and sources of the digital files that NHGIS has integrated into its system.
Scanned versions of many print census publications are also available through the U.S. Census Bureau's Publications site.
1790-1960
- Historical Demographic, Economic and Social Data: The United States, 1790-2002 (ICPSR 2896)
- ICSPR Study 2896 is the secondary source of most of NHGIS's pre-1970 nation, state and county-level tables, including population, housing, manufacturing, and religious bodies data.
- This is also the source of all NHGIS agricultural census data for years 1840-1910 and for all tables in these NHGIS datasets: 1850_1959_cFV, 1920_cPHAM, 1920_sOccFarmer, 1930_cPAE, 1940_cPHAE, 1950_cPHA
- Updates in either the ICPSR or NHGIS data may have produced incomplete correspondence.
- For more information, see ICPSR's Study 2896 page.
- Historical Demographic, Economic and Social Data: The United States, 1790-1970 (ICPSR 3)
- ICPSR Study 3 is an earlier version of ICPSR 2896 with a smaller scope and was used by NHGIS for its initial data development.
- Where ICPSR 2896 deviates from ICPSR 3, NHGIS data may correspond to either source, depending on which updates were available at the time NHGIS added the data.
- For more information, see ICPSR's Study 3 page.
1910, 1920 & 1930 Tract & Enumeration District Data
Summaries of data provided by Andrew Beveridge, Queens College, City University of New York:
- Beveridge SAS Datasets Contents Sheet for 1910 Cities
- Beveridge 1920 Final SAS Dataset Contents for Cities
- Beveridge 1930 Final SAS Dataset Contents for Cities
1915-1972 Vital Statistics: Natality & Mortality Data
The 1915-1967 births and deaths data are derived from printed annual reports of the U.S. Census Bureau (1915-1944) and the U.S. Public Health Service (1945-1967), most of which are available as PDF documents through this repository of the National Center for Health Statistics.
The 1968-1972 data are derived from individual-level microdata (either birth certificates or the Compressed Mortality File) from the National Center for Health Statistics.
Michael Haines at Colgate University provided NHGIS with the digital source data.
1970-2007 Vital Statistics: Natality & Mortality Data
The 1970-2007 births and deaths data (in dataset 1970_2007_cVS) are derived from the USA Counties database of the U.S. Census Bureau, which includes birth and death data from the National Center for Health Statistics (NCHS) and population estimates from the U.S. Census Bureau Population Estimates program.
WARNING: Where county boundary changes occurred, the population estimates may be based on *different* county boundary definitions than the birth and death counts. In some cases, NHGIS has attempted to standardize the counts and rates to describe consistent county definitions. Elsewhere, NHGIS supplies a note to indicate where inconsistencies may occur. In these cases, the reported birth and death rates may be inaccurate and should be interpreted with caution.
NHGIS supplies flags and note codes for these data records within output NHGIS data files. The flag text is provided completely within the output file. The notes corresponding to the note codes are given in the NHGIS 1970-2007 Vital Statistics Notes file.
Documentation for the original USA Counties database is provided through these Excel files:
- Mastgroups - The generalized group classification of data
- Mastdata - Individual data names and descriptions
- Source - Source provider of data
- Footnote Reference - Footnotes applied to some records
- Flag Reference - Reference description and ID of flags used in data collection
1867-2010 Vital Statistics: Marriage & Divorce Data
The 1867-2010 marriage and divorce data (in dataset 1867_2010_cMD) were compiled by the National Center for Family and Marriage Research (NCFMR) at Bowling Green State University. NCFMR researchers derived the 2000 and 2010 data from county court record information obtained through individual state or county agencies. They derived the earlier data from print reports from the U.S. Bureau of Labor (1867-1886), the U.S. Census Bureau (1890, 1900, 1916, 1922-1932), the National Office of Vital Statistics (1949-1950, 1952, 1957-1958), and the National Center for Health Statistics (1959-1987).
NHGIS supplies note codes for these data records in output NHGIS data files. The notes corresponding to the note codes are given in the NHGIS 1867-2010 Marriage and Divorce Data Notes file.
1920-1935 Census of Agriculture Data
- United States Agriculture Data, 1840-2012
- This data series, compiled by Michael Haines (Colgate University), Price Fishback (University of Arizona) and Paul Rhode (University of Michigan), is also available as ICPSR Study 35206
- Many of the datasets in this series were derived directly from ICPSR Study 3 or 2896, resulting in overlaps in series content.
- NHGIS used this source for all of its detailed agricultural datasets (those with "cAg" codes) for 1920 and later years.
1920-1936 Bank Deposit Data
- Federal Deposit Insurance Corporation Data on Banks in the United States, 1920-1936 (ICPSR 7)
- At the time NHGIS added this dataset, it was a part of ICPSR Study 3.
1940, 1950 & 1960 Tract Data
- Census Tract Data, 1940: Elizabeth Mullen Bogue File (ICPSR 2930)
- Census Tract Data, 1950: Elizabeth Mullen Bogue File (ICPSR 2931)
- Census Tract Data, 1960: Elizabeth Mullen Bogue File (ICPSR 2932)
Decennial Census Summary Files (1960-2010)
1960
1970
1980
Core summary files
- STF1: Summary Tape File 1. Technical Documentation
- STF2: Summary Tape File 2. Technical Documentation
- STF3: Summary Tape File 3. Technical Documentation
- STF4: Summary Tape File 4. Technical Documentation
Special & supplementary summary files
- CASRS: County Population by Age, Sex, Race, and Spanish Origin
- EEO: Equal Employment Opportunity Special File
- GQASRS: Group Quarters Population by Age, Sex, Race, and Spanish Origin
- JTW: Journey-to-Work
- MIG: County Migration by Selected Characteristics, 1975-1980
- PL94: P.L. 94-171 Population Counts
- TRCTMCD: Person and Housing Unit Counts for Tracts and Minor Civil Divisions
1990
Core summary files
- STF1: Summary Tape File 1. Technical Documentation
- STF2: Summary Tape File 2. Technical Documentation
- STF3: Summary Tape File 3. Technical Documentation
- STF4: Summary Tape File 4. Technical Documentation (Part 1)
- STF4: Summary Tape File 4. Technical Documentation (Part 2)
- STF4: Summary Tape File 4. Technical Documentation (Part 3)
- STF4: Summary Tape File 4. Technical Documentation (Part 4)
Special & supplementary summary files
- MARS: Modified Age/Race, Sex, and Hispanic Origin Files
- PL94-171: Public Law 94-171 Data
- SSTF01: Subject Summary Tape File 1. The Foreign-Born Population in the United States
- SSTF02: Subject Summary Tape File 2. Ancestry of the Population in the United States
- SSTF03: Subject Summary Tape File 3. Persons of Hispanic Origin in the United States
- SSTF04: Subject Summary Tape File 4. Characteristics of Adults with Work Disabilities, Mobility Limitations, or Self-Care Limitations
- SSTF05: Subject Summary Tape File 5. The Asian and Pacific Islander Population in the United States
- SSTF06: Subject Summary Tape File 6. Education in the United States
- SSTF07: Subject Summary Tape File 7. Metropolitan Housing Characteristics
- SSTF08: Subject Summary Tape File 8. Housing of the Elderly
- SSTF09: Subject Summary Tape File 9. Housing Characteristics of New Units
- SSTF10: Subject Summary Tape File 10. Mobile Homes
- SSTF12: Subject Summary Tape File 12. Employment Status, Work Experience, and Veteran Status
- SSTF13: Subject Summary Tape File 13. Characteristics of American Indians by Tribe and Language
- SSTF14: Subject Summary Tape File 14. Occupation and Industry
- SSTF15: Subject Summary Tape File 15. Geographic Mobility in the United States
- SSTF16: Subject Summary Tape File 16. Fertility
- SSTF17: Subject Summary Tape File 17. Poverty Areas in the United States
- SSTF18: Subject Summary Tape File 18. Condominium Housing
- SSTF19: Subject Summary Tape File 19. The Older Population of the United States
- SSTF21: Subject Summary Tape File 21. Characteristics of the Black Population
- SSTF22: Subject Summary Tape File. Earnings by Occupation and Education
- STF420: Summary Tape File 420. Place of Work, 20 Destinations File
- STP14A: Special Tabulation Program 14A. Special Tabulation on Aging
2000
- SF1: Summary File 1. Technical Documentation
- SF1: Summary File 1 Supplement, States
- SF2: Summary File 2
- SF2: Summary File 2 Supplement
- SF3: Summary File 3
- SF4: Summary File 4
- EEO: Equal Employment Opportunity Tabulation Guidance for Data Users [Census Bureau website]
2010
- P.L. 94-171 Redistricting Data Summary File: Technical Documentation
- SF1: Summary File 1: Technical Documentation
- SF2: Summary File 2: Technical Documentation
2020
- P.L. 94-171 Redistricting Data Summary File: Technical Documentation
- DHC: Demographic and Housing Characteristics File: Technical Documentation
County Business Patterns
1970-1973
1974-1987
1988-1997
- CBP1987_1988: County Business Patterns, 1987 and 1988
- CBP1989_1990: County Business Patterns, 1989 and 1990
- CBP1991_1992: County Business Patterns, 1991 and 1992
- CBP1993_1994: County Business Patterns, 1993 and 1994
- CBP1995_1996: County Business Patterns, 1995 and 1996
- CBP1997: County Business Patterns, 1997
- ZipCBP1994: Zip Code Business Patterns, 1994
- ZipCBP1995: Zip Code Business Patterns 1995
- ZipCBP1996: Zip Code Business Patterns 1996
1998-2003
- CBP1998: County Business Patterns 1998
- CBP1999: County Business Patterns 1999
- CBP2000: County Business Patterns 2000
- CBP2001: County Business Patterns 2001
- CBP2002: County Business Patterns 2002
- ZipCBP1998: Zip Code Business Patterns 1998
- ZipCBP1999: Zip Code Business Patterns 1999
- ZipCBP2000: Zip Code Business Patterns 2000
- ZipCBP2001: Zip Code Business Patterns 2001
- ZipCBP2002: Zip Code Business Patterns 2002
American Community Survey
Technical Documentation
- 2009 5-Year Summary File
- 2010 1-Year Summary File
- 2010 3-Year Summary File
- 2010 5-Year Summary File
- 2011 1-Year Summary File
- 2011 3-Year Summary File
- 2011 5-Year Summary File
- 2012 1-Year Summary File
- 2012 3-Year Summary File
- 2012 5-Year Summary File
- 2013 Summary Files
- 2014 Summary Files
- 2015 Summary Files
- 2016 Summary Files
- 2017 Summary Files
- 2018 - 2019 Summary Files: Using the American Community Survey Summary File: What Data Users Need to Know
- 2020 - 2023 Summary Files: Using the American Community Survey Table-Based Summary File: What Data Users Need to Know
- Beginning with the 2020 5-Year Summary File, NHGIS has obtained ACS summary file data from the new table-based format. Beginning with the 2022 1-Year Summary File, the Census Bureau stopped publishing the older "sequence-based format" and provided only the table-based format.
- The table-based format uses a different set of special "jam values"--a set corresponding to the values given by the Census API rather than the values used in the sequence-based format of Summary Files. The new set uses negative numeric values almost exclusively rather than the "." character that was previously typical.
- For pre-2020 releases of ACS Summary Files, NHGIS replaced "." jam values with blanks in data extracts using the comma delimited (.csv) format, but we still provided the "." values in fixed-width output files.
- To streamline our processing of the new format, we replace all negative values with blanks universally.
Subject Definitions
- 2009 Subject Definitions
- 2010 Subject Definitions
- 2011 Subject Definitions
- 2012 Subject Definitions
- 2013 Subject Definitions
- 2014 Subject Definitions
- 2015 Subject Definitions
- 2016 Subject Definitions
- 2017 Subject Definitions
- 2018 Subject Definitions
- 2019 Subject Definitions
- 2020 Subject Definitions
- 2021 Subject Definitions
- 2022 Subject Definitions
- 2023 Subject Definitions
Code Lists