- Lead
- 15,799
- Total
- 120,752
- vs nation
- D+14.6
California 31st State House District
President margin by year
Place winner margin
President results by year
Modeled candidate-vote estimate on current district boundaries
- Lead
- 42,423
- Total
- 141,382
- vs nation
- D+25.6
- Lead
- 35,628
- Total
- 111,944
- vs nation
- D+29.7
- Lead
- 29,504
- Total
- 99,915
- vs nation
- D+25.7
- Lead
- 31,749
- Total
- 105,313
- vs nation
- D+22.9
- Lead
- 12,160
- Total
- 89,909
- vs nation
- D+16.0
- Lead
- 14,388
- Total
- 82,411
- vs nation
- D+16.9
- Lead
- 19,245
- Total
- 79,278
- vs nation
- D+15.8
Key facts
- 2024 presidential margin
- D+13.1MIT Election Lab
- Population
- 495,4652024 5-year
- Population density
- 857 / sq mi2024 5-year · TIGER/Line
- Land area
- 578 sq miTIGER/Line
- Median household income
- $59,3602024 5-year
- White (non-Hispanic)
- 15.3%2024 5-year
- Black
- 5.9%2024 5-year
- Hispanic / Latino
- 64.2%2024 5-year
- Peak Democratic margin
- D+86.4 in 1876MIT Election Lab
- Peak Republican margin
- R+15.6 in 1924MIT Election Lab
- Most similar
- Assembly District 45, CA · twin score 97.9
presidential history
Party record book
California 31st State House District · the strongest Democratic and Republican presidential performances recorded here, measured three ways.
1892–2024 (partial returns from 1876) · 38 presidential cycles · 38 with a vote-share denominator · 34 with a national benchmark
Highest vote share
Largest share of the presidential candidate vote cast here.
Democratic
Samuel J. Tilden1876
93.2%
437 votes · D+86.4 · modeled estimate
Runner-up · Winfield S. Hancock, 1880 · 86.9%
Republican
George W. Bush2004
42.7%
38,413 votes · D+13.5 · modeled estimate
Runner-up · Donald Trump, 2024 · 42.1%
Most votes
Largest number of votes cast for the party’s presidential nominee here.
Democratic
Joe Biden2020
90,468votes
64.0% of the vote · D+30.0 · modeled estimate
Runner-up · Hillary Clinton, 2016 · 69,270 votes
Republican
Donald Trump2024
50,815votes
42.1% of the vote · D+13.1 · modeled estimate
Runner-up · Donald Trump, 2020 · 48,045 votes
Best relative to the U.S.
This Place’s margin against the national margin in the same election — positive when it leaned toward the party more than the country did.
Democratic
William J. Bryan1896
+67.1pts D vs U.S.
Place D+61.0 · U.S. R+6.1 · modeled estimate
Runner-up · Adlai Stevenson, 1956 · +56.0 pts
Republican
Calvin Coolidge1924
−9.6pts R vs U.S.
Place R+15.6 · U.S. R+25.2 · a third-party candidate carried the Place · modeled estimate
Runner-up · Donald Trump, 2024 · −14.6 pts
Current officeholders
State legislative officeholder from OpenStates nightly current-legislator data.
Senate and governor results are in the Office selector at the top of this page.
U.S. House
Each row is a county-allocated estimate of U.S. House votes for this district — county returns apportioned onto its boundary, not precinct-counted. “Vote lead” is the estimated local lead here, not necessarily the winner of the full contest.
| Year | Vote lead | Democratic | Republican | Total |
|---|---|---|---|---|
| 2018 | D | 51.9%63,703 | 48.1%59,065 | 122,768 |
California 31st State House District sits in the Pacific Coast. In 2024 it voted Democratic.
Across the recorded series it reached a Democratic high of 86.4 points in 1876 and a Republican high of 15.6 points in 1924. Between 2020 and 2024 the district moved 16.9 points toward the Republican candidate; the 2024 margin was 13.1 points.
A population of 495,465, a 15% non-Hispanic-white share, and a median household income of $59,360 describe the district. The district's voting pattern over the last decade is most similar to that of Assembly District 45 and Assembly District 50.
The state-house districts whose fingerprint — 2000–2024 trajectory, demographics, ancestry, religion — sits closest to this one, and why.
Twin score (0–100) = weighted cosine between tier-standardized fingerprints: presidential margins 2000–2024 with 12-yr trend and elasticity, ACS income, age, education, population and race, top reported ancestries, and religious adherence — chips name the closest-shared dimensions and the widest gap. Re-weight the groups in the twins explorer.
District research tools
Open the source-auditable district brief for electoral baseline, electorate, current-cycle coverage, geography, official dates, and methodology. Open campaign intelligence report → · Browse all comparisons →
California 31st State House District. Akashic. https://akashic.app/sld-lower/06031/. Accessed May 20, 2026. License: CC BY 4.0.