How Trump, Harris, and Newsom Fared in California’s Proposed Districts

Last week, California’s proposed new congressional maps were released. While the initial rollout provided some high-level information — mostly voter registration and census data — we thought it was important to do a deeper dive. Registration numbers and demographics can be useful indicators, but they only tell part of the story. To really understand how these districts might behave, you need to see how the same voters have actually cast ballots in the past.

That’s where our database comes in. We’ve built a robust archive of precinct-level election results going back more than a decade (by utilizing data from California's Statewide Database). By overlaying the new district boundaries onto those historical precinct results, we can re-tally past elections as if the new lines had been in place all along. This gives a clearer picture of partisan lean and electoral history than registration data alone.

The only caveat is Madera County — its 2024 precinct data hasn’t yet been fully processed. Any new districts that overlap Madera won’t show complete 2024 results until that processing is finished.

What Each Row Means

• 2024 Presidential (Trump vs. Harris)

  This row shows how voters in the district cast their ballots in the 2024 presidential election. The percentages include every vote, even for third-party candidates, and the margin highlights who came out ahead and by how much.

• 2022 Governor (Newsom vs. Dahle)

  Here we show the two-candidate results from the governor’s race. The margin makes it easy to see which candidate carried the district and by what size.

• 2024 Congressional (Old Boundaries)

  This captures the general election results under the current district lines, but only if there was a Democrat-versus-Republican matchup. If the race was between two candidates of the same party, or no major-party contest took place, this row will say “No data.”

• 2024 Congressional (New Boundaries – Precinct Estimate)

  This is our estimate of what the 2024 congressional race would have looked like if the new lines had been in place. We add up all the Democratic and Republican votes from precincts inside the proposed district and report the margin. Think of it as a descriptive snapshot of partisan lean under the new boundaries, not a forecast of future elections. If a district overlaps Madera County (where 2024 precinct data is still being processed) or only had a same-party race, we do not show an estimate.

• Party Registration Advantage (2024 General)

  For the current (old) districts, registration figures come from Political Data Inc. For the new districts, we use the registration counts included in the officially submitted map data. These numbers show the difference between registered Democrats and Republicans as of the 2024 general election. For example, “D+6.4” means Democrats make up 6.4 percentage points more of the major-party registration than Republicans. If the two are tied, it will say “Even.”

• District Overlap

  Redistricting always means change, but some districts change more than others. This row shows what percentage of people from the old district remain in the new one. A higher number suggests more continuity, while a lower number signals a district that has been significantly reshaped.

Subscribers to The Ballot Book can access the full dataset behind these tables, including complete historical election results and voter metrics for every district statewide.

District-by-District Analysis