- Lead
- 1,838
- Total
- 10,237
- vs nation
- D+19.4
Montana 31st State Senate District
President margin by year
Place winner margin
President results by year
Modeled candidate-vote estimate on current district boundaries
- Lead
- 2,858
- Total
- 11,795
- vs nation
- D+19.8
- Lead
- 1,636
- Total
- 9,290
- vs nation
- D+15.5
- Lead
- 1,077
- Total
- 8,040
- vs nation
- D+9.5
- Lead
- 1,796
- Total
- 8,231
- vs nation
- D+14.5
- Lead
- 259
- Total
- 6,525
- vs nation
- D+6.4
- Lead
- 514
- Total
- 5,202
- vs nation
- R+10.4
- Lead
- 224
- Total
- 4,890
- vs nation
- R+3.9
Key facts
- 2024 presidential margin
- D+18.0MIT Election Lab
- Population
- 21,6002024 5-year
- Population density
- 1,510 / sq mi2024 5-year · TIGER/Line
- Land area
- 14.3 sq miTIGER/Line
- Median household income
- $78,3662024 5-year
- White (non-Hispanic)
- 84.6%2024 5-year
- Black
- 0.6%2024 5-year
- Hispanic / Latino
- 5.9%2024 5-year
- Peak Democratic margin
- D+69.2 in 1896MIT Election Lab
- Peak Republican margin
- R+25.7 in 1952MIT Election Lab
- Most similar
- State Senate District 9, WY · twin score 95.8
presidential history
Party record book
Montana 31st State Senate District · the strongest Democratic and Republican presidential performances recorded here, measured three ways.
1892–2024 · 34 presidential cycles
Highest vote share
Largest share of the presidential candidate vote cast here.
Democratic
William J. Bryan1896
84.6%
362 votes · D+69.2 · modeled estimate
Runner-up · Franklin D. Roosevelt, 1936 · 71.7%
Republican
Dwight D. Eisenhower1952
62.5%
947 votes · R+25.7 · modeled estimate
Runner-up · Dwight D. Eisenhower, 1956 · 57.4%
Most votes
Largest number of votes cast for the party’s presidential nominee here.
Democratic
Joe Biden2020
7,051votes
59.8% of the vote · D+24.2 · modeled estimate
Runner-up · Kamala Harris, 2024 · 5,849 votes
Republican
Donald Trump2020
4,193votes
35.5% of the vote · D+24.2 · modeled estimate
Runner-up · Donald Trump, 2024 · 4,011 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
William J. Bryan1896
+75.2pts D vs U.S.
Place D+69.2 · U.S. R+6.1 · modeled estimate
Runner-up · William J. Bryan, 1900 · +35.4 pts
Republican
Dwight D. Eisenhower1952
+15.0pts R vs U.S.
Place R+25.7 · U.S. R+10.8 · modeled estimate
Runner-up · Gerald Ford, 1976 · +11.4 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 |
|---|---|---|---|---|
| 2020 | D | 54.4%6,703 | 45.6%5,609 | 12,312 |
| 2018 | D | 57.5%5,448 | 42.5%4,031 | 9,479 |
In 2024 it voted Democratic by D+18.0, against D+21.8 in 2008. In the 2024 ACS 5-year, 54.3% of adults held a bachelor's degree or higher.
Across the recorded series it reached a Democratic high of 69.2 points in 1896 and a Republican high of 25.7 points in 1952. Between 2020 and 2024 the district moved 6.3 points toward the Republican candidate; the 2024 margin was 18.0 points.
A population of 21,600, a 85% non-Hispanic-white share, and a median household income of $78,366 describe the district. The district's voting pattern over the last decade is most similar to that of State Senate District 9 and State Senate District 32.
The state-senate 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 →
Montana 31st State Senate District. Akashic. https://akashic.app/sld-upper/30031/. Accessed May 20, 2026. License: CC BY 4.0.