Following the post-2010 Census redistricting process, the Census Bureau collected state legislative district boundaires from all states. These were the boundaries in effect for the 2012 election cycle.

These Block Equivalency Files (BEFs) are the whole 2010 Census tabulation block representations of the 2012 State Legislative District plans as submitted by the states to the U.S. Census Bureau. The .ZIP file contains a national block equivalency file and individual state files for all states, the District of Columbia, and Puerto Rico. The fields in these files should be imported as text to preserve leading zeros.

In instances where plans included split 2010 Census tabulation blocks, the Census Bureau requested that the state assign the whole block to one district for the purpose of tabulating data. These block equivalency files contain the whole block tabulation plan. The Census Bureau's maps and TIGER/Line shapefiles depict the correct location of the boundary (splits tabulation blocks). A listing of those blocks split in the states' official plans, and which district the population of these blocks is tabulated to, is also provided.

Ohio split blocks in their 2012 State Legislative District- Upper Chamber (SLDU) and State Legislative District- Lower Chamber (SLDL) plans. Delaware and the District of Columbia split blocks in their SLDU plans. Connecticut and Vermont split blocks in their SLDL plan. 

The 2013 TIGER/Line products include the 2012 State Legislative Districts. The state legislative district boundaries are the boundaries as submitted by the state liaisons in Phase 4 of the Redistricting Data Program.

The shapefiles for the state legislative districts are identified by their abbreviation within the file name: "sldu" for the state legislative districts - upper house; and "sldl" for the state legislative districts - lower house.

The State Legislative District (SLD) Reference maps display the boundaries, names, and/or codes of SLDs in effect for the 2012 election cycle. 

Two separate map types make up this series: one that displays State Legislative Districts – Upper Chamber (SLDUs) and one that displays State Legislative Districts – Lower Chamber (SLDLs). Each of these maps shows the extent of the subject SLDs, as well as the surrounding SLDs of the same type.