Civic data / Ohio · adopted 2022 and 2025 plans · fixed 2020 population
Ohio, redrawn
Follow population across two sets of congressional boundaries.
Same Ohio. Different district boundaries.
Orange shows reassigned territory. We match old and new districts by the greatest total retained population across all 15 pairs. Here, every matched pair keeps the same district number.
Prior plan · adopted March 2022
New plan · adopted October 2025
Common 2020 TIGER blocks; display simplified to 200 metres. Water is included in these outlines. These are reconstructed analytical maps, not official address-lookup maps. Use the Ohio Secretary of State for official district information.
| Old district | New district | 2020 population | Share of old |
|---|
Counties and Census places
Populated splits: 14 → 15 counties and 41 → 55 Census places. A place is a 2020 incorporated place or Census-designated place, not every kind of community. Blocks outside places are excluded from the place table.
| Name | Reassigned population | Old districts with population | New districts with population | Reassigned land km² |
|---|
A split counts an entity appearing in more than one district. Downloaded tables also count splits touching zero-population blocks and population outside each entity’s largest district piece. Fewer splits alone does not establish a better plan.
Inspect the full transition matrix
Rows are old districts; columns are new districts. Each cell counts 2020 population assigned to that pair. All cells sum to 11,799,448. Both plans have a one-person difference between their largest and smallest districts.
Show all 225 population cells
Take the numbers with you
Geometry descriptors use unsimplified reconstructed polygons in EPSG:5070: area, perimeter, Polsby–Popper, convex-hull area ratio, and polygon parts. Shorelines and water affect these measures; none measures partisan fairness. See methods, source checksums, and reproduction guide.
Inside the study
METHODS / STATUS / NEXT USEQuestion
How did adopted Ohio congressional boundaries change between the March 2, 2022 plan and the October 31, 2025 plan first used in the 2026 election cycle?
Data
Official commission block-assignment workbooks, 2020 Census PL 94-171 population, Census place assignments and TIGER/Line blocks: 276,428 common blocks and 11,799,448 people in the fixed 2020 population base.
Methods
Validate the complete block universe; construct a 15×15 population crosswalk; maximize one-to-one population overlap to avoid mistaking renumbering for reassignment; compare county/place splits and population balance. Reconstruct district polygons from blocks for geometric descriptors; simplify only display geometry.
Tests already recorded
Existing test-results.txt records 10 passing tests, including renumbering and matching counterexamples. build-status.json says complete. validation.md records source reconciliation, geometry checks and local browser checks; full assistive-technology user testing remains pending.
Findings
1,478,290 people in the fixed 2020 counts (12.53%) fall in reassigned blocks. Populated county splits increase 14→15 and populated Census-place splits 41→55. Each plan’s largest-minus-smallest district population is one person. Optimal matching pairs same-numbered districts without assuming that outcome.
Caveats
These are fixed 2020 counts, not present-day residents, voters or migration. Census places are an incomplete community proxy. Shape descriptors do not establish fairness, illegality or election outcomes. Secretary of State SHAPE/XLSX downloads were inaccessible (403); commission assignments and reconstructed geometry are not claimed byte-identical to those files.
Technical work produced
Block joins, overlap matching, population and split tables, reconstructed geometry checks, simplified display GeoJSON and an offline interactive explorer with downloadable aggregate tables.
Human review and contribution still pending
Confirm adopted-plan identity; trace a transition cell; review reconstructed maps against official PDFs; evaluate the community proxy and keyboard/screen-reader experience. Review redistribution terms before any future public release.
Prospective real-world use: Community lookup and boundary-change handouts
Ask whether a resident-information desk, library program or civics class has a real need to explain local boundary changes. If invited, offer a relevant community handout or offline lookup demonstration for its existing activity and obtain any required institutional approval. No recipient or institution has agreed to use it.
What already exists
The offline explorer supports Census-place search, county summaries, district transitions and downloadable aggregate tables. It already provides a basis for a place/county-level lookup; it is not an address-to-district service.
Functional adaptation still needed
A future authorized adaptation would create printable, accessible change handouts for selected communities using the existing tables and maps, label both plans and the fixed 2020 population base, explain place boundaries, and point residents to official election information for address-specific questions. Libraries or civics classes might prefer a short guided exercise. Determine their requested geography and format first; do not build an address lookup from these outputs or imply the handout already exists.
Adoption and outcome evidence
Adoption: actual inclusion of a handout or explorer exercise in a library information workflow or class activity and any repeat use. Outcome: whether users can correctly identify a community-level change and explain why the population is from 2020, plus task completion time and unresolved lookup questions. Record accessibility problems. Views or compliments do not establish usefulness or civic outcomes.
AI assistance and current status
The user supplied or authorized the project goal and scope. AI substantially produced the initial code, tests, analysis execution, charts and documentation. This case-study draft is also AI-written. No completed independent user coding, source audit, beneficiary review, adoption or measured impact is recorded. Passing software checks does not establish subject-matter validity. Update this wording only with evidence of work actually performed.
Sources & aggregate downloads
Built from completed outputs retrieved October 1, 2026. These are fixed snapshots, not live data. Official source. Output provenance and checksums.
Aggregate outputs only. No raw records are included. These materials remain a private review preview; source terms and disclosure need review before any future public release.