Geographic boundary data for Michigan, Kentucky, and Iowa¶
Michigan offers the best precinct data availability among these three states, with 2024 voting precincts freely downloadable in multiple formats. Iowa provides official precinct shapefiles through its Secretary of State but as individual county files requiring assembly. Kentucky presents the greatest challenge: despite state law mandating digital precinct file submission, no centralized public download exists—researchers must contact election officials directly or rely on academic compilations from VEST and the Redistricting Data Hub.
State and county boundaries are universally accessible¶
All three states have free, ready-to-use state and county boundary data from multiple sources. The Census Bureau’s TIGER/Line program provides the authoritative national standard, with 2024/2025 vintages currently available in shapefile format at https://www.census.gov/cgi-bin/geo/shapefiles/index.php.
Each state also maintains its own GIS portal with equivalent data:
| State | Portal | County Data URL | Formats Available |
|---|---|---|---|
| Michigan | Michigan GIS Open Data | gis-michigan.opendata.arcgis.com | SHP, GeoJSON, KML, CSV |
| Kentucky | KYGEONET Open Data | opengisdata.ky.gov | SHP, GeoJSON, KML, CSV, GeoTIFF |
| Iowa | Iowa Geodata | geodata.iowa.gov | SHP, GeoJSON, KML, CSV |
Census TIGER/Line files update annually in September. State portals update as needed, though county boundaries rarely change. All sources are free with no registration required.
Municipal and township boundaries require layered sourcing¶
Census TIGER/Line provides two complementary datasets: “Places” (incorporated cities, towns, Census Designated Places) and “County Subdivisions” (townships, MCDs). Both are available for all three states in 2024 vintage.
Michigan excels here with dedicated layers on its Open Data Portal for Minor Civil Divisions, cities, and villages—maintained by the Center for Shared Solutions with annual updates. Kentucky’s KYGEONET offers a “Ky City Boundary Polygon” layer for incorporated cities. Iowa’s Geodata clearinghouse includes municipal boundaries within its framework data collection.
For most analytical purposes, combining Census Places with County Subdivisions provides complete coverage. Format is uniformly shapefile; preprocessing needs are minimal.
School district data comes from education agencies and Census¶
| State | Best State Source | Census TIGER/Line | Recency |
|---|---|---|---|
| Michigan | MI GIS Open Data (v17a) | 2022 (2021-22 school year) | Current |
| Kentucky | KYGEONET School Districts | 2024 (2023-24 school year) | Current |
| Iowa | Iowa Dept of Education | 2022-23 school year | 2024-25 available |
Iowa Department of Education provides the most current school district boundaries, with 2024-25 school year files already published at geodata.iowa.gov. These are updated annually each school year. The direct link for current Iowa school districts: https://educate.iowa.gov/pk-12/district-maps.
Census TIGER/Line separates school districts into elementary, secondary, and unified district files— important because many states have overlapping district types. All school district data is free and ready to use without preprocessing.
Voting precincts reveal stark differences in state data practices¶
This is the most critical boundary type and shows dramatic variation in availability across the three states.
Michigan leads with comprehensive public precinct data¶
Michigan GIS Open Data Portal provides the gold standard: complete statewide voting precinct boundaries for 2014, 2016, 2018, 2020, 2022, and 2024 election cycles, all freely downloadable without account registration in shapefile, GeoJSON, and KML formats.
- 2024 precincts: https://gis-michigan.opendata.arcgis.com/datasets/Michigan::2024-voting-precincts
- Historical years: Same portal, each year separately available
- Data authority: Michigan Bureau of Elections with county/local GIS validation
- Update frequency: Each election cycle
- Preprocessing: Ready to use; no cleaning required
Michigan’s data quality caveat: boundaries are “only as good as the information received from the local election official”—some jurisdictions don’t fully validate submissions.
Iowa provides official precincts but requires assembly¶
Iowa Secretary of State publishes city and county precinct shapefiles based on 2020 Census redistricting, effective March 15, 2022. These remain valid through 2031.
- City precincts: https://sos.iowa.gov/shapefiles-city-precincts (150+ individual city files)
- County precincts: https://sos.iowa.gov/shapefiles-county-precincts (all 99 counties)
- Format: Shapefile (.zip)
- Cost: Free
- Limitation: No single statewide file—must download and merge county files
For pre-compiled statewide data with election results, use Redistricting Data Hub or VEST (see below).
Kentucky lacks public precinct access despite legal mandate¶
Kentucky presents the most challenging scenario. KRS 117.055 (amended 2024) legally requires county boards of elections to submit digital precinct boundaries in ESRI shapefile or geodatabase format to the State Board of Elections. However, these files are not published online.
To obtain current Kentucky precinct boundaries:
- Contact Kentucky State Board of Elections (elect.ky.gov) directly—may require formal records request
- Use individual county GIS portals for major counties:
- Jefferson County (Louisville): https://data.lojic.org/datasets/jefferson-county-ky-voting-precincts
- Fayette County (Lexington): https://data.lexingtonky.gov
- Use historical data from VEST/RDH for 2016, 2019, 2020 elections
Historical note: Kentucky did not submit VTDs to the Census Bureau for the 2010 Census. While 2020 Census VTDs exist, they may not match current operational precincts.
Academic and nonprofit sources fill critical gaps¶
Three organizations provide invaluable precinct data compilations, especially for election analysis:
VEST (Voting and Election Science Team) at Harvard Dataverse¶
VEST produces “the most comprehensive database of precinct boundaries and associated statewide election results.” All three states have coverage:
| State | Years Available | URL |
|---|---|---|
| Michigan | 2016, 2018, 2020 | doi:10.7910/DVN/K7760H |
| Kentucky | 2016, 2019, 2020 | dataverse.harvard.edu/dataverse/electionscience |
| Iowa | 2016, 2018, 2020 | doi:10.7910/DVN/K7760H |
Format: ESRI shapefile with election results pre-joined. Cost: Free, no registration. Preprocessing: Cleaned and validated.
Redistricting Data Hub¶
The RDH (redistrictingdatahub.org) aggregates data from VEST, MGGG, and state sources:
- Michigan: https://redistrictingdatahub.org/state/michigan/
- Kentucky: https://redistrictingdatahub.org/state/kentucky/
- Iowa: https://redistrictingdatahub.org/state/iowa/
Format: Shapefile and CSV. Cost: Free with account registration. Includes election results disaggregated to 2020 Census blocks for redistricting analysis.
MGGG (Metric Geometry and Gerrymandering Group)¶
For Michigan specifically, MGGG provides high-quality shapefiles with dual graphs for GerryChain redistricting analysis: https://github.com/mggg-states/MI-shapefiles. Rated “A” for data quality—obtained directly from state government.
Comparison matrix for voting precinct availability¶
| Attribute | Michigan | Iowa | Kentucky |
|---|---|---|---|
| Current boundaries available | ✅ 2024 | ✅ 2022 (valid to 2031) | ⚠️ Request required |
| Official state download | ✅ Yes | ✅ Yes (per-county) | ❌ No |
| Statewide single file | ✅ Yes | ❌ Assembly required | ❌ No |
| Election results joined | ❌ (separate) | ❌ (separate) | ❌ (separate) |
| VEST/RDH historical | ✅ 2016-2020 | ✅ 2016-2020 | ✅ 2016-2020 |
| Formats | SHP, GeoJSON, KML | SHP | SHP (from RDH) |
| Registration required | No | No | N/A (RDH: Yes) |
| FOIA/request needed | No | No | Yes (for current) |
| Update frequency | Each election | Decennial | Unknown |
What requires work versus what’s ready to use¶
Ready immediately (no work required):¶
- All states: State boundaries, county boundaries, school districts via Census TIGER/Line or state portals
- Michigan: All boundary types including current 2024 precincts
- Iowa: State/county/municipal boundaries; school districts from DOE
- Kentucky: State/county/municipal boundaries; school districts from KYGEONET
Requires assembly or processing:¶
- Iowa precincts: Download and merge 99 county files from SOS, or use VEST/RDH pre-compiled versions
- Kentucky precincts (historical): Available through VEST/RDH but requires free account registration
Requires direct outreach:¶
- Kentucky current precincts: Contact State Board of Elections or individual county election offices
- Any state’s 2024 election results + precincts combined: Not yet available from VEST (expected 2025)
Recommended workflow for each state¶
Michigan: Use Michigan GIS Open Data Portal (gis-michigan.opendata.arcgis.com) as primary source for all boundary types. For election analysis with results, supplement with VEST data from Harvard Dataverse.
Iowa: Use Iowa Secretary of State (sos.iowa.gov) for official precincts by county. For school districts, use Iowa DOE directly (most current data). For a pre-compiled statewide precinct file with election results, use Redistricting Data Hub.
Kentucky: Start with KYGEONET (opengisdata.ky.gov) for administrative boundaries. For precincts, use VEST or RDH for historical data (2016-2020). For current precincts, submit a formal request to Kentucky State Board of Elections at elect.ky.gov, or check individual county GIS portals for major counties.
Key URLs for direct access¶
| Resource | URL |
|---|---|
| Census TIGER/Line | census.gov/cgi-bin/geo/shapefiles/index.php |
| Michigan Open Data | gis-michigan.opendata.arcgis.com |
| Kentucky KYGEONET | opengisdata.ky.gov |
| Iowa Geodata | geodata.iowa.gov |
| Iowa SOS Precincts | sos.iowa.gov/precinct-and-district-shapefiles |
| Redistricting Data Hub | redistrictingdatahub.org |
| VEST Harvard Dataverse | dataverse.harvard.edu/dataverse/electionscience |
| MGGG Michigan | github.com/mggg-states/MI-shapefiles |
Conclusion¶
The availability of voting precinct boundaries—the most analytically valuable and hardest-to-find boundary type—varies dramatically by state governance practices rather than technical capability. Michigan’s transparent, centralized approach yields the best user experience: current data in multiple formats, no registration, immediate download. Iowa’s county-by-county structure requires more effort but provides official, current boundaries. Kentucky’s gap between legal requirements and public access creates the most friction, forcing researchers toward academic compilations or direct government requests.
For all three states, the Redistricting Data Hub and VEST at Harvard Dataverse serve as essential fallback sources, providing cleaned, election-result-joined precinct boundaries for 2016-2020 elections. The 2024 election cycle data from these academic sources will likely become available throughout 2025.