The Census Bureau's Redistricting Data Products provide the states and other data users with the small area census data necessary for legislative redistricting. Among the geographic products disseminated for the 2010 Census are the Block Assignment Files (BAFs) and corresponding Name Look-up Tables (NLTs).
BAFs have been created for each of the 50 states, the District of Columbia, and Puerto Rico. Each file contains 2010 Census tabulation block codes and geographic area codes for a specific geographic entity type. Each BAF contains every block within the given state, even if the block is not within one of the geographic areas represented in the file. For those blocks where no geographic area is present, the block is listed, followed by one or more commas (depending on the file layout for the specific geographic area type).
The file naming convention is as follows:
where <ss> is the 2-character state FIPS code, <USPSabbrev> is the 2-letter U.S. Postal Service (USPS) state abbreviation, and <entity> is the geography area type being represented.
BAFs are comma delimited text (.txt) files. The first line of each BAF is the field header. The 9 types of BAFs and the fields they contain are described below:
|Geographic Area||<entity>||Field Layout|
|State legislative districts - upper||SLDU||BLOCKID,DISTRICT|
|State legislative districts - lower||SLDL||BLOCKID,DISTRICT|
|Elementary school districts||SDELM||BLOCKID,DISTRICT|
|Secondary school districts||SDSEC||BLOCKID,DISTRICT|
|Unified school districts||SDUNI||BLOCKID,DISTRICT|
|Incorporated places / census designated places||INCPLACE_CDP||BLOCKID,PLACEFP|
|American Indian / Alaska Native / Native Hawaiian areas||AIANNH||BLOCKID,AIANNHCE,COMPTYPE|
Field definitions are as follows: