Description

IPUMS USA cannot identify most counties in recent samples.

COUNTYICP identifies the county where the household was enumerated, using the Inter-University Consortium for Political and Social Research (ICPSR) coding scheme.

COUNTYICP codes are state-dependent; they must be combined with state codes (see STATEICP or STATEFIP) to distinguish counties located in different states.

Many county boundaries and some county names have changed over time. IPUMS does not impose a uniform county boundary system on the data, so each county listed for a given year in IPUMS should be assumed to have the boundaries that it had in that year.

All counties are identified in 1850 to 1950 full count files. Counties are not identified in public-use microdata samples from 1950 onwards, so IPUMS instead identifies counties, where possible, from other low-level geographic identifiers. These include State Economic Areas (SEA) in the 1950 1% sample; county groups in 1970 samples (CNTYGP97) and 1980 samples (CNTYGP98); and Public Use Microdata Areas (PUMA) from 1990 onwards, including Super-PUMAs (PUMASUPR) in 2000.

In 1950 and later samples (excluding the 1950 full count), COUNTYICP identifies a county if and only if:

• it was coterminous with a single SEA, county group, or PUMA; or

• it contained multiple SEAs, county groups, or PUMAs, none of which extended into other counties.

List of counties identified in 1950 and later samples:

• Identified Counties, 1950-Forward

For municipios, the Puerto Rican statistical equivalent of U.S. counties, see PRCOUNTA (alphabetic version) and PRCOUNTY (numeric version).

ICPSR county codes are generally ordered alphabetically by county name within states. With a few exceptions, ICPSR codes correspond to 3-digit FIPS codes (as identified by 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.

Like STATEICP, COUNTYICP facilitates merging IPUMS data with ICPSR data. COUNTYICP also identifies areas that were not part of any county, including the independent cities of Virginia and some Indian lands.

COUNTYICP is a 4-digit numeric variable that identifies the county where the household was enumerated using the Inter-University Consortium for Political and Social Research (ICPSR) coding scheme. See ICPSR County Codes for a detailed listing of the codes.

COUNTYICP codes are state-dependent; they must be combined with state codes (see STATEICP or STATEFIP) to distinguish counties located in different states.

Correspondence with FIPS Codes:
Most ICPSR codes correspond to 3-digit FIPS codes (as identified by COUNTYFIP) followed by an added zero digit.

The only systematic discrepancies between ICPSR and FIPS codes occur in Maryland, where all FIPS codes of 009 and higher (excluding Baltimore City, which has FIPS code 510 and ICPSR code 5100) are shifted down by two in the ICPSR scheme. For example, Calvert County has FIPS code 009 and ICPSR code 0070.

In Nevada, Pershing County has FIPS code 027 and historical Ormsby County has FIPS code 025. In the ICSPR scheme, Pershing County has code 0250, and Ormsby County uses the Carson City county code of 0510. (Ormsby County was consolidated with Carson City in 1969.) The historical (1870) Rio Virgin County uses ICPSR county code 0270.

COUNTYICP-Specific Variable Codes
0000 = County not identifiable from public-use data (1950-onward)

Comparability

This variable is comparable across years, but county boundaries change over time. For more information about changes to counties, see the Census Bureau’s page on Substantial Changes to Counties and County Equivalent Entities: 1970-Present.

It is worth noting that the Census Bureau changed the statistical units for Connecticut from ‘counties’ to the county-equivalent unit, ‘planning regions’, starting with the 2022 ACS. Connecticut counties identified in COUNTYICP for the 2022 ACS and forward are these new planning regions identified by the Census Bureau.

COUNTYICP codes are generally compatible with the ICSPR codes in historical county boundary files from IPUMS NHGIS and with all ICPSR county-level data files.

Universe

Availability

• 2023: All samples
• 2022: All samples
• 2021: All samples
• 2020: All samples
• 2019: All samples
• 2018: All samples
• 2017: All samples
• 2016: All samples
• 2015: All samples
• 2014: All samples
• 2013: All samples
• 2012: All samples
• 2011: All samples
• 2010: All samples
• 2009: All samples
• 2008: All samples
• 2007: All samples
• 2006: All samples
• 2005: All samples
• 2004: --
• 2003: --
• 2002: --
• 2001: --
• 2000: 5%; 1% old; 1% unwt; 1%
• 1990: 5% state; 1% metro; 1% unwt
• 1980: 5% state; 1% metro
• 1970: 1% metro fm1; 1% metro fm2
• 1960: 5%
• 1950: All samples
• 1940: All samples
• 1930: All samples
• 1920: All samples
• 1910: All samples
• 1900: All samples
• 1880: All samples
• 1870: All samples
• 1860: All samples
• 1850: All samples

• 2023: --
• 2022: --
• 2021: --
• 2020: --
• 2019: --
• 2018: --
• 2017: --
• 2016: --
• 2015: --
• 2014: --
• 2013: --
• 2012: --
• 2011: --
• 2010: --
• 2009: --
• 2008: --
• 2007: --
• 2006: --
• 2005: --
• 2000: --
• 1990: --
• 1980: --
• 1970: --
• 1930: --
• 1920: --
• 1910: --

Flags

Editing Procedure

There is no editing procedure available for this variable.