Terms and licence
What you may do with what is published here, where the numbers come from, and what this site does not claim to be.
Last updated 20 September 2026
Using the figures
The figures, charts, maps and written analysis published on District Lines are released under the Creative Commons Attribution 4.0 International licence (CC BY 4.0).
You are free to copy and redistribute this material in any medium or format, and to remix, transform and build upon it for any purpose, including commercially. In exchange, you must give appropriate credit, link to the licence, and indicate whether you made changes. You may not apply legal terms or technological measures that stop anyone else doing the same.
A citation looks like this:
District Lines, “Projection Desk”, districtlines.org, retrieved 20 September 2026.
If you are writing about a specific number, linking to the page it came from is worth more to a reader than quoting it, because the page carries the uncertainty alongside the estimate.
What the licence does not cover
- The source code. The pipeline, models, validation harness and redistricting scorer behind this site are not published and are not licensed for reuse. All rights reserved.
- The underlying public data. District Lines does not own the election returns, boundary files or census measures it builds on, and does not purport to license them. Those remain governed by the terms of the bodies that publish them, listed below. Facts are not ours to give away or to withhold.
- The name and the wordmark. “District Lines” and the mark used on this site are not covered by the content licence.
Where the data comes from
Everything here is built from public sources. Each page names the specific source behind the view you are looking at; this is the full list.
| Source | Used for | Their terms |
|---|---|---|
| U.S. Census Bureau | Boundaries, block equivalency files, ACS measures, apportionment | U.S. government work, public domain |
| Federal Election Commission | Certified results, candidate and committee filings, spending | U.S. government work, public domain |
| MIT Election Data and Science Lab | U.S. House and Senate returns, 1976–2024 | Published under CC BY; cite MEDSL directly if you reuse it |
| Redistricting Data Hub | 2020 results disaggregated to census blocks | Free account required at source; attribution requested |
| State election authorities | Candidate lists, precinct returns, early vote files | Varies by state; generally public record |
| Wikipedia | Generic-ballot aggregate readings, some candidate details | CC BY-SA. Only factual values are taken, never prose |
On that last row: District Lines reads numbers and names from Wikipedia tables and does not copy its text. Individual facts are not subject to copyright, so taking them does not make this site a derivative work and does not pull it under share-alike. Where a reading can be taken directly from the aggregator that produced it, it is.
What this site is not
District Lines publishes estimates. An estimate carries error, and the error is reported next to it wherever it is known: held-out backtest scores, simulated ranges, and coverage figures on every disaggregation.
- A projection is a probability, not a prediction. An outcome given a 23% chance is expected to happen roughly one time in four. That it happened does not make the projection wrong.
- Some inputs are estimates of estimates. Votes assigned to census blocks are allocated from precinct totals, not observed. State legislative districts are small enough that this matters more there than for a congressional seat.
- Source data changes. Candidate lists, certified returns and court rulings move. Pages carry the date their data was built.
- Nothing here is legal, electoral or financial advice, and nothing here is a finding about any redistricting plan's lawfulness. Voting-age population is not citizen voting-age population, and a majority on this site's measure is a prompt to look closer, not a legal conclusion.
The material is provided as is, without warranty of any kind, express or implied. District Lines is not liable for any decision taken in reliance on it.
Privacy
This site sets no cookies, runs no analytics, and embeds no trackers or advertising. Nothing you do here is recorded or profiled, and there is no account to create.
The Atlas page stores a single timestamp in your browser's sessionStorage to keep a failed map load from reloading in a loop. It never leaves your browser, it is not an identifier, and closing the tab discards it.
Two files are loaded from third parties: the d3 charting library from cdnjs and the typefaces from Google Fonts. Those providers see the request your browser makes for them. Everything else is served from this domain.
Corrections and contact
If a number here looks wrong, it may well be, and a specific report is the fastest way to get it fixed — the page, the district and what you expected instead. Corrections that change a published figure are noted on the page that carried it.
Write to contact@districtlines.org.