For directions on reading the variable description see Data Dictionary Introduction.

Availability: 
 

1850	1860	1870	1880	1900	1910	1920	1940	1950	1960	1970	1980	1990
												X

Universe: 
All households and group quarters. 

Description/Comparability: 
This unrecoded variable reports the household’s Public Use Microdata Area (PUMA) of residence. In the State sample, PUMAs generally follow the boundaries of county groups, single counties, or census-defined places; if these areas exceed 200,000 residents, they are divided into as many 100,000+ PUMAs as possible. None of the State sample PUMAs cross state lines. For the Metro sample, they generally follow the boundaries of whole central cities, Metropolitan Statistical Areas, Primary Metropolitan Statistical Areas, or non-metropolitan places. If these areas exceed 200,000 residents, they are divided into as many 100,000+ PUMAs as possible. Metro sample PUMAs sometimes cross state lines; when they do, STATEFIP and STATEICP codes are not available for households in those PUMAs. 

Note that PUMA is state-dependent. It must be read in combination with one of the STATE variables (STATEFIP or STATEICP). PUMAs are categorized by type (e.g., metropolitan, mixed metro/nonmetro) in the variable PUMATYPE. This variable is available only for 1990, but it is similar to the county group variables, CNTYGP97 and CNTYGP98. 

Codes: 
Original 1990 PUMS maps and detailed composition data of the PUMAs (both by state and in one large downloadable file), can be found at the 1990 PUMAs page on the IPUMS web site. A separate section describing the contents of PUMAs that cross state boundaries in the Metro sample can be found at the "99" File page on the Ipums web site.