The file naming convention for the 2020 Redistricting Data (P.L. 94-171) Block Assignment Files (BAFs), 2020 Redistricting Data Prototype (P.L. 94-171) Block Assignment Files (BAFs): 2018 End-to-End Test, and the 2010 Census Block Assignment Files is as follows:

     BlockAssign_ST<ss>_<USPSabbrev>_<entity>.txt

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.