I am using the American Community Survey (ACS) Public Use Microdata Sample (PUMS) data, and I see a geographic area called PUMA. What are Public Use Microdata Areas (PUMAs)?
Public Use Microdata Areas (PUMAs) are non-overlapping areas that partition each state into areas containing about 100,000 residents. PUMAs were developed to be the most detailed geographic area available in the Public Use Microdata Samples (PUMS). Because the State Data Centers (SDCs) and their partner organizations help define these areas for the Census Bureau, they should be meaningful to many data users.
PUMA boundaries are updated with each decennial census in cooperation with the SDCs. For more information, visit the Public Use Microdata Areas page. American Community Survey PUMS files will begin to use the new 2010 PUMA boundaries for PUMS data released in 2013.
PUMA Mapping Resources
PUMAs were first made available in the 2005 ACS 1-year PUMS files and have been included in every PUMS release since then. ACS PUMS files from 2000-2004 did not include the PUMA variable.