ICPSR County Codes: 1850-1930

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This page lists the codes used in the variable COUNTY, which employs the coding scheme of the Inter-University Consortium for Political and Social Research (ICPSR). The first 3 digits are identical to the FIPS county codes used in other datasets; ICPSR adds a digit to accomodate change over time (generally, if a county merged with another or was renamed before 1970, it receives a fourth digit of "5"). A full list of ICPSR County Codes can also be downlowded as an Excel file or as tab-delimitted text.

County boundary files are available for the years listed below.

IPUMS data can be matched to these files using the STATEICP and COUNTY variables.