- Lead
- 64,896
- Total
- 355,916
- vs nation
- D+19.7
California 51st Congressional District
President margin by year
Place winner margin
President results by year
Modeled candidate-vote estimate on current district boundaries
- Lead
- 88,993
- Total
- 389,001
- vs nation
- D+18.4
- Lead
- 61,953
- Total
- 324,567
- vs nation
- D+17.0
- Lead
- 20,477
- Total
- 296,073
- vs nation
- D+3.1
- Lead
- 29,206
- Total
- 306,001
- vs nation
- D+2.3
- Lead
- 19,012
- Total
- 281,903
- vs nation
- R+4.3
- Lead
- 10,784
- Total
- 237,768
- vs nation
- R+5.1
- Lead
- 4,455
- Total
- 219,126
- vs nation
- R+10.6
Key facts
- 2024 presidential margin
- D+18.2MIT Election Lab
- Population
- 757,5862024 5-year
- Population density
- 1,279 / sq mi2024 5-year · TIGER/Line
- Land area
- 592 sq miTIGER/Line
- Median household income
- $107,4102024 5-year
- White (non-Hispanic)
- 50.8%2024 5-year
- Black
- 6.6%2024 5-year
- Hispanic / Latino
- 27.0%2024 5-year
- Peak Democratic margin
- D+44.7 in 1912MIT Election Lab
- Peak Republican margin
- R+43.1 in 1904MIT Election Lab
- Most similar
- Congressional District 50, CA · twin score 91.3
presidential history
Party record book
California 51st Congressional 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
63.2%
15,950 votes · D+27.8 · modeled estimate
Runner-up · Joe Biden, 2020 · 60.3%
Republican
Herbert Hoover1928
66.5%
11,775 votes · R+34.6 · modeled estimate
Runner-up · Ronald Reagan, 1984 · 65.5%
Most votes
Largest number of votes cast for the party’s presidential nominee here.
Democratic
Joe Biden2020
234,572votes
60.3% of the vote · D+22.9 · modeled estimate
Runner-up · Kamala Harris, 2024 · 205,227 votes
Republican
George W. Bush2004
148,640votes
52.7% of the vote · R+6.7 · modeled estimate
Runner-up · Donald Trump, 2020 · 145,579 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
+25.1pts D vs U.S.
Place D+44.7 · U.S. D+19.5 · a third-party candidate carried the Place · modeled estimate
Runner-up · Kamala Harris, 2024 · +19.7 pts
Republican
Ronald Reagan1980
+24.3pts R vs U.S.
Place R+34.1 · U.S. R+9.7 · modeled estimate
Runner-up · Barry Goldwater, 1964 · +23.8 pts
Current officeholders
Federal officeholders only. State and local officeholders are planned for the next data pass.
Senate and governor results are in the Office selector at the top of this page.
U.S. House
Each result reflects the U.S. House district as it was drawn for that election; redistricting has redrawn these lines over time, so they can differ from the current 120th-Congress district shown on the map above.
California's 51st stretches along the Tijuana border crossing, one of the busiest land ports in the world, giving it a heavily Latino electorate and consistent double-digit Democratic margins in federal races.
Across the recorded series it reached a Democratic high of 44.7 points in 1912 and a Republican high of 43.1 points in 1904. Between 2020 and 2024 the district moved 4.6 points toward the Republican candidate; the 2024 margin was 18.2 points.
A population of 757,586, a 51% non-Hispanic-white share, and a median household income of $107,410 describe the district. The district's voting pattern over the last decade is most similar to that of Congressional District 50 and Congressional District 16.
The congressional 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 51st Congressional District. Akashic. https://akashic.app/cd/0651/. Accessed May 20, 2026. License: CC BY 4.0.