Six states (Alabama, Alaska, Colorado, Minnesota, North Carolina, and Utah) and the District of Columbia delineated new boundaries for the 2018 election cycle. All other states and Puerto Rico had no changes to their state legislative district boundaries from the 2016 cycle.

These Block Equivalency Files (BEFs) are the whole 2010 Census tabulation block representations of the 2018 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 who reported changes during this collection cycle. 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.

Three states split blocks in their 2022 State Legislative District- Upper Chamber (SLDU) and State Legislative District- Lower Chamber (SLDL) plans: Minnesota, Ohio, and Utah. Delaware and the District of Columbia split blocks in their SLDU plans. Connecticut and Vermont split blocks in their SLDL plan. 

The 2018 – 2022 TIGER/Line products include the 2018 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 2018 election cycle. Six states and the District of Columbia delineated new boundaries for the 2018 election cycle. New maps were created only for the District of Columbia and the states with SLD changes since the 2016 cycle (Alabama, Alaska, Colorado, Minnesota, North Carolina, and Utah). All other states continue to maintain their previous state legislative district boundaries.

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 SLD, as well as the surrounding SLDs of the same type.

The 2018 State Legislative District Relationship Files provide simple relationships between 2018 State Legislative Districts and other 2010 Census tabulation geography including American Indian areas, counties, county subdivisions, census tracts, places, school districts, urban/rural population and land area, and ZIP Code Tabulation Areas.