National Post-Redistricting (2021 Cycle) State Legislative District Boundaries and Block Assignment File ## RDH Creation Date 03/08/2023 ## Sources This file is intended to represent the first state legislative boundaries drawn using 2020 PL census data that an election has been or will be held on. We do not plan on updating this file unless any of the following states and levels update their maps before elections: KS SLDU, LA SLDL, LA SLDU, MS SLDL, MS SLDU, NJ SLDL, NJ SLDU, NM SLDU, SC SLDU, VA SLDL and VA SLDU. These are state chambers that to date have not held elections using the newly enacted maps, and therefore could change before an election in 2023 or 2024 is held. The main source for the district shapefiles is the U.S. Census, SLDL source [here](https://www2.census.gov/geo/tiger/TIGER_RD18/LAYER/SLDL/) and SLDU source [here](https://www2.census.gov/geo/tiger/TIGER_RD18/LAYER/SLDU/). The main source for the block-assignment file is the U.S. Census, source [here](https://www2.census.gov/programs-surveys/decennial/rdo/mapping-files/2023/2022-state-legislative-bef/). Block-assignment file data for MN and CO was substituted with official block-assignment files from the respective states. For SLDU, this results in one block with 0 total population being assigned differently in Colorado and seven blocks with 28 total population being assigned differently in Minnesota. For SLDL, this results in five blocks with 12 total population being assigned differently in Colorado and ten blocks with 37 total population being assigned differently in Minnesota. Although the Census' file contains "22" in the field name, we determined that there files included data for the first state legislative boundaries drawn using 2020 PL census data that an election has been or will be held on. As such, in the handful of instances when a state either did not pass a new state legislative redistricting plan as of February 2023, or did pass a new plan, but did not hold an election on those districts, the data comes from the "National Pre-2021 Redistricting State Legislative Boundaries" file available on the RDH website. These include the following states and legislative levels: KS SLDU, LA SLDL, LA SLDU, MS SLDL, MS SLDU, MT SLDL, MT SLDU, NJ SLDL, NJ SLDU, NM SLDU, SC SLDU, VA SLDL and VA SLDU. Montana's SLDL and SLDU plans had not been finalized when the census released its shapefilzs and block-assignment files, this data is swapped in from an official BAF and shapefile from the state. In New Hampshire, a handful of SLDL district names were corrected manually. New Hampshire floterial districts were created using a mapping from base districts to floterial districts provided by a state official. Please note that NH is the only the state with both base and floterial districts. The floterial districts are stored in a separate file to prevent unintentional overlaps in processing. ## Fields Field Name Description ***national_post_2021_redistricting_st_leg_boundaries_baf.csv*** GEOID20 2020 Census Block GEOID SLDU State Legislative Upper House District Name or Number SLDL State Legislative Lower House District Name or Number FLOTERIAL Floterial District Name or Number ***national_post_2021_redistricting_st_leg_lower_nh_floterial_boundaries*** DISTRICT District Name or Number STATE State Abbreviation ***national_post_2021_redistricting_st_leg_lower_boundaries*** DISTRICT District Name or Number STATE State Abbreviation ***national_post_2021_redistricting_st_leg_upper_boundaries*** DISTRICT District Name or Number STATE State Abbreviation ## Processing Notes The data in these block-assignment files were compared against those created using the maup software package on the official redistricting plans. In every instance, when the correct maps were being compared, the census' block-assignments matched against our block-assignments for every block with population, except for in New Hampshire, Delaware, North Dakota, Minnesota and Colorado. For New Hampshire, the census' assignments match a document with district-level population totals we received from the state. Delaware and North Dakota both contained split blocks in their official plans, and as there is no "right answer", we just used what is in the census file. For Minnesota and Colorado, the states provide official BAFs and although the Census says they verify split blocks and use what the state tells them, what the census has differs from the official block-assignment files. ## Additional Notes In the BAF, the "FLOTERIAL" field is not applicable and marked "NO FLOTERIAL" for all states except New Hampshire. In New Hampshire, the state legislative lower house has both base districts (represented by the 'SLDL' field) and floterials (represented by the "FLOTERIAL" field). Not all blocks in New Hampshire are nested within a floterial and those that are not are assigned "NO VALUE" in the "FLOTERIAL" field. District names in MA SLDL, VT SLDL, VT SLDU, and NH SLDL were modified slightly to match those of official state maps. For states with one map for state legislative districts, the same values were used for the "SLDL" and "SLDU" fields. Nebraska is an exception to this, as it does not have a lower chamber in its state legislature, so for the "SLDL" field all blocks are assigned "NO SLDL". Some blocks may not have assignments for SLDU or SLDL districts. These blocks are given "NO VALUE" in their respective fields. When creating the district shapefiles, "NO VALUE" and "NO SLDL" districts are filtered out. Please email info@redistrictingdatahub.org for any questions about this dataset.