- Lead
- 16,991
- Total
- 453,094
- vs nation
- D+5.2
California 40th State Senate District
President margin by year
Place winner margin
President results by year
Modeled candidate-vote estimate on current district boundaries
- Lead
- 31,544
- Total
- 481,561
- vs nation
- D+2.1
- Lead
- 2,408
- Total
- 389,057
- vs nation
- R+2.7
- Lead
- 51,009
- Total
- 364,972
- vs nation
- R+17.8
- Lead
- 43,059
- Total
- 376,039
- vs nation
- R+18.7
- Lead
- 97,979
- Total
- 358,267
- vs nation
- R+24.9
- Lead
- 73,955
- Total
- 299,726
- vs nation
- R+25.2
- Lead
- 57,869
- Total
- 274,536
- vs nation
- R+29.6
Key facts
- 2024 presidential margin
- D+3.7MIT Election Lab
- Population
- 950,2032024 5-year
- Population density
- 750 / sq mi2024 5-year · TIGER/Line
- Land area
- 1,266 sq miTIGER/Line
- Median household income
- $120,7632024 5-year
- White (non-Hispanic)
- 48.3%2024 5-year
- Black
- 2.0%2024 5-year
- Hispanic / Latino
- 26.1%2024 5-year
- Peak Democratic margin
- D+38.9 in 1912MIT Election Lab
- Peak Republican margin
- R+55.3 in 1904MIT Election Lab
- Most similar
- State Senate District 37, CA · twin score 93.0
presidential history
Party record book
California 40th 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
Franklin D. Roosevelt1936
52.5%
15,633 votes · D+6.8 · modeled estimate
Runner-up · Joe Biden, 2020 · 52.1%
Republican
Herbert Hoover1928
75.4%
17,899 votes · R+52.5 · modeled estimate
Runner-up · Ronald Reagan, 1984 · 74.5%
Most votes
Largest number of votes cast for the party’s presidential nominee here.
Democratic
Joe Biden2020
250,991votes
52.1% of the vote · D+6.6 · modeled estimate
Runner-up · Kamala Harris, 2024 · 228,470 votes
Republican
George W. Bush2004
226,157votes
63.1% of the vote · R+27.3 · modeled estimate
Runner-up · Donald Trump, 2020 · 219,447 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
Woodrow Wilson1912
+19.3pts D vs U.S.
Place D+38.9 · U.S. D+19.5 · a third-party candidate carried the Place · modeled estimate
Runner-up · Kamala Harris, 2024 · +5.2 pts
Republican
Barry Goldwater1964
+45.1pts R vs U.S.
Place R+22.5 · U.S. D+22.6 · modeled estimate
Runner-up · William H. Taft, 1908 · +40.0 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.
The district recorded a Democratic presidential margin of D+3.8 in 2024 and R+11.5 in 2008, switching sides at least once in between. No racial group formed a majority of its residents in the 2024 ACS 5-year, with White residents at 48.4%.
Across the recorded series it reached a Democratic high of 38.9 points in 1912 and a Republican high of 55.3 points in 1904. Between 2020 and 2024 the district moved 2.8 points toward the Republican candidate; the 2024 margin was 3.7 points.
A population of 950,203, a 48% non-Hispanic-white share, and a median household income of $120,763 describe the district. The district's voting pattern over the last decade is most similar to that of State Senate District 37 and State Senate District 13.
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 40th State Senate District. Akashic. https://akashic.app/sld-upper/06040/. Accessed May 20, 2026. License: CC BY 4.0.