Description

For households located in an incorporated place (city, village, town, etc.), PLACENHG identifies the place of residence, using the IPUMS National Historical Geographic Information System (NHGIS) coding scheme for historical places.

These codes also appear in NHGIS place point shapefiles, in the NHGISPLACE attribute field. NHGIS place point files identify the locations of places for use in mapping and spatial analysis. Users who generate summaries of place characteristics from IPUMS USA microdata may join their summaries to the place point files by matching the PLACENHG and NHGISPLACE codes.

PLACENHG codes are 10-character place identifiers. The first character is a "G", which prevents applications from automatically reading the identifier as a number and, in effect, dropping important leading zeros. The next 3 characters give the NHGIS state code, and the last 6 characters give the NHGIS historical place code.

Because PLACENHG codes include a state identifier, they distinguish each place uniquely for the entire country, not just within each state.

NHGIS state codes generally correspond to the 2-digit state FIPS codes (as given by STATEFIP) with a third digit appended to distinguish historical U.S. territories. For states that exist today, the NHGIS state code is exactly the FIPS code + "0".

For places that are identified in recent census summary data (1990 or later), the first 5 digits of the 6-digit place component of PLACENHG codes correspond to the standard place FIPS code, and the last digit is "0". PLACENHG codes ending in "5" identify historical places that do not appear in recent census data. In these cases, NHGIS created a new code that fits within the alphabetical ordering of the FIPS system.

A code of "9999999999" indicates that the household did not reside within an identifiable incorporated place.

Listing of identified places:

• PLACENHG Code List

The code list identifies the state and place name corresponding to each PLACENHG code. Because PLACENHG is currently available only for 1940 microdata, the list uses place names from the 1940 NHGIS place point file. We will update the list with additional names as we release PLACENHG for other years.

In cases where a place’s name varies slightly over time (e.g., in spelling, spacing, case, or punctuation), the code list generally reports the most recent version of the name, which may differ from the original census records. In cases where a place had a major name change (e.g., from "Richmond" to "Grand River"), the code list gives the name or names used in the years in which the code appears in microdata. (In these cases, the PLACENHG code may appear to be out of order, as codes are ordered alphabetically for only one of the names of each place, usually the most recent.)

Comparability

Each PLACENHG code refers to a single place across time, but place boundaries may change substantially due to annexations, mergers, etc.

Universe

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Flags

Editing Procedure

There is no editing procedure available for this variable.