- Lead
- 22,382
- Total
- 293,928
- vs nation
- D+9.1
California 31st State Senate District
President margin by year
Place winner margin
President results by year
Modeled candidate-vote estimate on current district boundaries
- Lead
- 80,970
- Total
- 332,052
- vs nation
- D+19.9
- Lead
- 70,180
- Total
- 251,195
- vs nation
- D+25.8
- Lead
- 55,619
- Total
- 219,527
- vs nation
- D+21.5
- Lead
- 56,075
- Total
- 214,257
- vs nation
- D+18.9
- Lead
- 13,743
- Total
- 175,857
- vs nation
- D+10.3
- Lead
- 25,207
- Total
- 147,514
- vs nation
- D+16.6
- Lead
- 24,827
- Total
- 130,429
- vs nation
- D+10.5
Key facts
- 2024 presidential margin
- D+7.6MIT Election Lab
- Population
- 950,5262024 5-year
- Population density
- 2,806 / sq mi2024 5-year · TIGER/Line
- Land area
- 339 sq miTIGER/Line
- Median household income
- $91,7872024 5-year
- White (non-Hispanic)
- 18.6%2024 5-year
- Black
- 8.0%2024 5-year
- Hispanic / Latino
- 62.3%2024 5-year
- Peak Democratic margin
- D+84.6 in 1880MIT Election Lab
- Peak Republican margin
- R+35.6 in 1924MIT Election Lab
- Most similar
- State Senate District 29, CA · twin score 99.5
presidential history
Party record book
California 31st State Senate 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
Winfield S. Hancock1880
92.3%
12 votes · D+84.6 · modeled estimate
Runner-up · Samuel J. Tilden, 1876 · 90.9%
Republican
Herbert Hoover1928
65.3%
4,526 votes · R+32.8 · modeled estimate
Runner-up · Warren G. Harding, 1920 · 53.7%
Most votes
Largest number of votes cast for the party’s presidential nominee here.
Democratic
Joe Biden2020
202,867votes
61.1% of the vote · D+24.4 · modeled estimate
Runner-up · Kamala Harris, 2024 · 153,663 votes
Republican
Donald Trump2024
131,281votes
44.7% of the vote · D+7.6 · modeled estimate
Runner-up · Donald Trump, 2020 · 121,897 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
Grover Cleveland1892
+35.1pts D vs U.S.
Place D+36.7 · U.S. D+1.7 · modeled estimate
Runner-up · George McGovern, 1972 · +27.6 pts
Republican
Herbert Hoover1928
+15.3pts R vs U.S.
Place R+32.8 · U.S. R+17.5 · modeled estimate
Runner-up · Calvin Coolidge, 1924 · +10.5 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 | 54.1%131,267 | 45.9%111,270 | 242,537 |
California 31st State Senate District sits in the Pacific Coast. In 2024 it voted Democratic.
Across the recorded series it reached a Democratic high of 84.6 points in 1880 and a Republican high of 35.6 points in 1924. Between 2020 and 2024 the district moved 16.8 points toward the Republican candidate; the 2024 margin was 7.6 points.
A population of 950,526, a 19% non-Hispanic-white share, and a median household income of $91,787 describe the district. The district's voting pattern over the last decade is most similar to that of State Senate District 29 and State Senate District 14.
The state-senate 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 Senate District. Akashic. https://akashic.app/sld-upper/06031/. Accessed May 20, 2026. License: CC BY 4.0.