- Lead
- 2,424
- Total
- 13,132
- vs nation
- D+19.9
Delaware 21st State House District
President margin by year
Place winner margin
President results by year
Modeled candidate-vote estimate on current district boundaries
- Lead
- 3,133
- Total
- 13,631
- vs nation
- D+18.5
- Lead
- 1,704
- Total
- 12,732
- vs nation
- D+11.3
- Lead
- 2,166
- Total
- 12,119
- vs nation
- D+14.0
- Lead
- 3,036
- Total
- 12,203
- vs nation
- D+17.6
- Lead
- 533
- Total
- 11,866
- vs nation
- D+6.9
- Lead
- 649
- Total
- 10,452
- vs nation
- D+5.7
- Lead
- 493
- Total
- 8,936
- vs nation
- R+3.0
Key facts
- 2024 presidential margin
- D+18.5MIT Election Lab
- Population
- 24,0502024 5-year
- Population density
- 2,586 / sq mi2024 5-year · TIGER/Line
- Land area
- 9.3 sq miTIGER/Line
- Median household income
- $101,2862024 5-year
- White (non-Hispanic)
- 72.1%2024 5-year
- Black
- 8.5%2024 5-year
- Hispanic / Latino
- 7.6%2024 5-year
- Peak Democratic margin
- D+24.9 in 2008MIT Election Lab
- Peak Republican margin
- R+50.1 in 1928MIT Election Lab
- Most similar
- State Representative District 25, DE · twin score 86.4
presidential history
Party record book
Delaware 21st 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
Barack Obama2008
61.6%
7,515 votes · D+24.9 · modeled estimate
Runner-up · Joe Biden, 2020 · 60.5%
Republican
Herbert Hoover1928
74.8%
2,858 votes · R+50.1 · modeled estimate
Runner-up · Calvin Coolidge, 1924 · 67.5%
Most votes
Largest number of votes cast for the party’s presidential nominee here.
Democratic
Joe Biden2020
8,252votes
60.5% of the vote · D+23.0 · modeled estimate
Runner-up · Kamala Harris, 2024 · 7,654 votes
Republican
Ronald Reagan1984
6,153votes
65.5% of the vote · R+31.4 · modeled estimate
Runner-up · Richard Nixon, 1972 · 6,054 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
Kamala Harris2024
+19.9pts D vs U.S.
Place D+18.5 · U.S. R+1.5 · modeled estimate
Runner-up · Joe Biden, 2020 · +18.5 pts
Republican
Herbert Hoover1932
+43.9pts R vs U.S.
Place R+26.1 · U.S. D+17.8 · modeled estimate
Runner-up · Herbert Hoover, 1928 · +32.7 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.
With a 2024 presidential margin of D+18.4, Delaware's 21st House district ranks among the state's more Democratic-leaning constituencies, reflecting the dense suburban and residential character typical of northern New Castle County.
Across the recorded series it reached a Democratic high of 24.9 points in 2008 and a Republican high of 50.1 points in 1928. Between 2020 and 2024 the district moved 4.5 points toward the Republican candidate; the 2024 margin was 18.5 points.
A population of 24,050, a 72% non-Hispanic-white share, and a median household income of $101,286 describe the district. The district's voting pattern over the last decade is most similar to that of State Representative District 25 and State Representative District 19.
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 →
Delaware 21st State House District. Akashic. https://akashic.app/sld-lower/10021/. Accessed May 20, 2026. License: CC BY 4.0.