- Lead
- 9,839
- Total
- 26,565
- vs nation
- D+38.5
Massachusetts 66th State House District
President margin by year
Place winner margin
President results by year
Modeled candidate-vote estimate on current district boundaries
- Lead
- 10,919
- Total
- 26,685
- vs nation
- D+36.5
- Lead
- 6,824
- Total
- 24,287
- vs nation
- D+26.0
- Lead
- 3,844
- Total
- 22,121
- vs nation
- D+13.5
- Lead
- 4,427
- Total
- 21,491
- vs nation
- D+13.3
- Lead
- 4,174
- Total
- 20,456
- vs nation
- D+22.9
- Lead
- 4,485
- Total
- 19,840
- vs nation
- D+22.1
- Lead
- 5,250
- Total
- 18,995
- vs nation
- D+19.1
Key facts
- 2024 presidential margin
- D+37.0MIT Election Lab
- Population
- 43,8132024 5-year
- Population density
- 631 / sq mi2024 5-year · TIGER/Line
- Land area
- 69.4 sq miTIGER/Line
- Median household income
- $184,2382024 5-year
- White (non-Hispanic)
- 79.8%2024 5-year
- Black
- 1.0%2024 5-year
- Hispanic / Latino
- 3.6%2024 5-year
- Peak Democratic margin
- D+45.7 in 1964MIT Election Lab
- Peak Republican margin
- R+55.2 in 1896MIT Election Lab
- Most similar
- 2nd Middlesex District, MA · twin score 98.3
presidential history
Party record book
Massachusetts 66th 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
72.6%
11,973 votes · D+45.7 · modeled estimate
Runner-up · Joe Biden, 2020 · 69.1%
Republican
Warren G. Harding1920
72.8%
4,886 votes · R+49.1 · modeled estimate
Runner-up · William McKinley, 1896 · 72.0%
Most votes
Largest number of votes cast for the party’s presidential nominee here.
Democratic
Joe Biden2020
18,427votes
69.1% of the vote · D+40.9 · modeled estimate
Runner-up · Kamala Harris, 2024 · 17,806 votes
Republican
Dwight D. Eisenhower1956
11,109votes
65.6% of the vote · R+31.5 · modeled estimate
Runner-up · Ronald Reagan, 1984 · 10,540 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
+38.5pts D vs U.S.
Place D+37.0 · U.S. R+1.5 · modeled estimate
Runner-up · Joe Biden, 2020 · +36.5 pts
Republican
William McKinley1896
+49.1pts R vs U.S.
Place R+55.2 · U.S. R+6.1 · modeled estimate
Runner-up · Alf Landon, 1936 · +35.5 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 | 97.2%16,547 | 2.8%479 | 17,026 |
| 2020 | D | 81.0%16,758 | 19.0%3,929 | 20,687 |
The 8th Middlesex delivered a 37.0-point Democratic presidential margin in 2024, reflecting the dense, highly educated suburban electorate characteristic of inner Middlesex County's legislative districts.
Across the recorded series it reached a Democratic high of 45.7 points in 1964 and a Republican high of 55.2 points in 1896. Between 2020 and 2024 the district moved 3.9 points toward the Republican candidate; the 2024 margin was 37.0 points.
A population of 43,813, a 80% non-Hispanic-white share, and a median household income of $184,238 describe the district. The district's voting pattern over the last decade is most similar to that of 2nd Middlesex District and 14th Norfolk District.
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 →
Massachusetts 66th State House District. Akashic. https://akashic.app/sld-lower/25066/. Accessed May 20, 2026. License: CC BY 4.0.