- Lead
- 69,597
- Total
- 219,361
- vs nation
- D+33.2
California 15th State House District
President margin by year
Place winner margin
President results by year
Modeled candidate-vote estimate on current district boundaries
- Lead
- 97,093
- Total
- 240,565
- vs nation
- D+35.9
- Lead
- 72,657
- Total
- 192,493
- vs nation
- D+35.7
- Lead
- 52,331
- Total
- 179,747
- vs nation
- D+25.3
- Lead
- 58,769
- Total
- 184,806
- vs nation
- D+24.5
- Lead
- 32,980
- Total
- 169,868
- vs nation
- D+21.9
- Lead
- 24,211
- Total
- 157,604
- vs nation
- D+14.8
- Lead
- 21,171
- Total
- 145,800
- vs nation
- D+6.0
Key facts
- 2024 presidential margin
- D+31.7MIT Election Lab
- Population
- 510,2722024 5-year
- Population density
- 1,578 / sq mi2024 5-year · TIGER/Line
- Land area
- 323 sq miTIGER/Line
- Median household income
- $112,9102024 5-year
- White (non-Hispanic)
- 37.1%2024 5-year
- Black
- 9.7%2024 5-year
- Hispanic / Latino
- 32.0%2024 5-year
- Peak Democratic margin
- D+40.4 in 2020MIT Election Lab
- Peak Republican margin
- R+50.9 in 1924MIT Election Lab
- Most similar
- Assembly District 4, CA · twin score 93.9
presidential history
Party record book
California 15th 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
Franklin D. Roosevelt1936
69.3%
10,160 votes · D+39.5 · modeled estimate
Runner-up · Joe Biden, 2020 · 69.0%
Republican
Warren G. Harding1920
67.9%
4,139 votes · R+46.9 · modeled estimate
Runner-up · Theodore Roosevelt, 1904 · 66.4%
Most votes
Largest number of votes cast for the party’s presidential nominee here.
Democratic
Joe Biden2020
166,089votes
69.0% of the vote · D+40.4 · modeled estimate
Runner-up · Kamala Harris, 2024 · 140,999 votes
Republican
Ronald Reagan1984
76,764votes
57.7% of the vote · R+16.4 · modeled estimate
Runner-up · Donald Trump, 2024 · 71,402 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
Joe Biden2020
+35.9pts D vs U.S.
Place D+40.4 · U.S. D+4.5 · modeled estimate
Runner-up · Hillary Clinton, 2016 · +35.7 pts
Republican
William H. Taft1908
+30.4pts R vs U.S.
Place R+40.0 · U.S. R+9.6 · modeled estimate
Runner-up · Calvin Coolidge, 1924 · +25.7 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.
Anchored in the Inland Empire's eastern reaches, AD-15 posts some of the largest Republican presidential margins in California, reflecting a working-class exurban base where cost-of-living pressures and slower demographic shifts diverge sharply from coastal districts.
Across the recorded series it reached a Democratic high of 40.4 points in 2020 and a Republican high of 50.9 points in 1924. Between 2020 and 2024 the district moved 8.6 points toward the Republican candidate; the 2024 margin was 31.7 points.
A population of 510,272, a 37% non-Hispanic-white share, and a median household income of $112,910 describe the district. The district's voting pattern over the last decade is most similar to that of Assembly District 4 and Assembly District 11.
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 15th State House District. Akashic. https://akashic.app/sld-lower/06015/. Accessed May 20, 2026. License: CC BY 4.0.