- Lead
- 9,235
- Total
- 39,777
- vs nation
- D+24.7
Pennsylvania 21st State House District
President margin by year
Place winner margin
President results by year
Modeled candidate-vote estimate on current district boundaries
- Lead
- 9,064
- Total
- 39,709
- vs nation
- D+18.4
- Lead
- 5,653
- Total
- 35,021
- vs nation
- D+14.1
- Lead
- 4,718
- Total
- 32,962
- vs nation
- D+10.5
- Lead
- 5,276
- Total
- 34,588
- vs nation
- D+8.0
- Lead
- 5,074
- Total
- 33,960
- vs nation
- D+17.4
- Lead
- 4,893
- Total
- 30,837
- vs nation
- D+15.3
- Lead
- 4,213
- Total
- 28,923
- vs nation
- D+6.0
Key facts
- 2024 presidential margin
- D+23.2MIT Election Lab
- Population
- 62,0062024 5-year
- Population density
- 3,229 / sq mi2024 5-year · TIGER/Line
- Land area
- 19.2 sq miTIGER/Line
- Median household income
- $85,8522024 5-year
- White (non-Hispanic)
- 87.3%2024 5-year
- Black
- 4.3%2024 5-year
- Hispanic / Latino
- 2.4%2024 5-year
- Peak Democratic margin
- D+33.5 in 1936MIT Election Lab
- Peak Republican margin
- R+55.9 in 1904MIT Election Lab
- Most similar
- State House District 20, PA · twin score 98.5
presidential history
Party record book
Pennsylvania 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
Lyndon B. Johnson1964
65.8%
24,964 votes · D+32.2 · modeled estimate
Runner-up · Franklin D. Roosevelt, 1936 · 64.5%
Republican
Theodore Roosevelt1904
73.5%
4,776 votes · R+55.9 · modeled estimate
Runner-up · William McKinley, 1896 · 70.1%
Most votes
Largest number of votes cast for the party’s presidential nominee here.
Democratic
Lyndon B. Johnson1964
24,964votes
65.8% of the vote · D+32.2 · modeled estimate
Runner-up · Kamala Harris, 2024 · 24,241 votes
Republican
Dwight D. Eisenhower1956
20,282votes
54.9% of the vote · R+10.0 · modeled estimate
Runner-up · Richard Nixon, 1972 · 19,586 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
Walter Mondale1984
+31.2pts D vs U.S.
Place D+13.0 · U.S. R+18.2 · modeled estimate
Runner-up · Michael Dukakis, 1988 · +27.3 pts
Republican
William McKinley1896
+37.4pts R vs U.S.
Place R+43.5 · U.S. R+6.1 · modeled estimate
Runner-up · Theodore Roosevelt, 1904 · +36.3 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 |
|---|---|---|---|---|
| 2024 | D | 58.9%20,751 | 41.1%14,482 | 35,233 |
Pennsylvania 21st State House District sits in the Mid-Atlantic. In 2024 it voted Democratic.
Across the recorded series it reached a Democratic high of 33.5 points in 1936 and a Republican high of 55.9 points in 1904. The 2024 margin was 23.2 points.
A population of 62,006, a 87% non-Hispanic-white share, and a median household income of $85,852 describe the district. The district's voting pattern over the last decade is most similar to that of State House District 20 and State House District 27.
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 →
Pennsylvania 21st State House District. Akashic. https://akashic.app/sld-lower/42021/. Accessed May 20, 2026. License: CC BY 4.0.