# County level data

**URL:** <https://forum.ipums.org/t/county-level-data/2458>\
**Category:** USA\
**Created:** [July 24, 2018, 5:33pm UTC](https://forum.ipums.org/t/county-level-data/2458 "2018-07-24T17:33:00Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![xw2017](https://avatars.discourse-cdn.com/v4/letter/x/bc8723/32.png) [@xw2017](https://forum.ipums.org/u/xw2017)\
**Post date:** [July 24, 2018, 5:33pm UTC](https://forum.ipums.org/t/county-level-data/2458/1 "2018-07-24T17:33:00Z")

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I know similiar questions have been asked, but I just want to make sure. In the COUNTY variable description page, there’s an [Excel spreadsheet](https://usa.ipums.org/usa/resources/volii/counties_1950_on.xls) provides a list of counties and their corresponding ICPSR and FIPS codes available in each year from 1950 onwards. So does it mean that there’s no county-level data in IPUMS for those counties that are not in list? Thanks.

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**Author:** ![JeffBloem](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.ipums.org/jeffbloem/32/40_2.png) [@JeffBloem](https://forum.ipums.org/u/JeffBloem)\
**Post date:** [July 24, 2018, 6:46pm UTC](https://forum.ipums.org/t/county-level-data/2458/2 "2018-07-24T18:46:00Z")

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Yes, that is correct. In samples from 1950 onward, counties are not identifiable in public use microdata. In these samples, some counties are identifiable in IPUMS USA due to alternative low-level geographic identifiers. The spreadsheet you linked above summarizes which counties are identifiable in which samples. If you are looking for aggregated data at the county level, you may find the data available via [IPUMS NHGIS](https://www.nhgis.org/) helpful.

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**Author:** ![Derek\_Thomas](https://avatars.discourse-cdn.com/v4/letter/d/ec9cab/32.png) [@Derek\_Thomas](https://forum.ipums.org/u/Derek_Thomas)\
**Post date:** [December 11, 2019, 4:52pm UTC](https://forum.ipums.org/t/county-level-data/2458/3 "2019-12-11T16:52:53Z")

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Hello,

Can you explain or point to an explanation of the differences between IPCSR and FIPS codes?

Thanks!

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**Author:** ![JeffBloem](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.ipums.org/jeffbloem/32/40_2.png) [@JeffBloem](https://forum.ipums.org/u/JeffBloem)\
**Post date:** [December 11, 2019, 5:26pm UTC](https://forum.ipums.org/t/county-level-data/2458/4 "2019-12-11T17:26:12Z")

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As is noted on the [COUNTYICP](https://usa.ipums.org/usa-action/variables/COUNTYICP#description_section) description tab: With [a few exceptions](https://usa.ipums.org/usa-action/variables/COUNTYICP#codes_section), ICPSR codes correspond to 3-digit FIPS codes (as identified by [COUNTYFIP](https://usa.ipums.org/usa-action/variables/COUNTYFIP)) followed by an added zero digit. The fourth digit is used to accommodate the complete history of U.S. county definitions. FIPS codes were instituted around the time of the 1970 census, and historical counties that were dissolved before then have no FIPS code. For such counties, ICPSR generally appends a fourth digit of 5.