Iowa 31st State Senate 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
67.3%
14,977 votes · D+34.7 · modeled estimate
Runner-up · Barack Obama, 2008 · 67.0%
Republican
Warren G. Harding1920
71.5%
6,223 votes · R+48.3 · modeled estimate
Runner-up · Herbert Hoover, 1928 · 63.1%
Most votes
Largest number of votes cast for the party’s presidential nominee here.
Democratic
Barack Obama2012
19,495votes
65.9% of the vote · D+33.4 · modeled estimate
Runner-up · Barack Obama, 2008 · 19,194 votes
Republican
Ronald Reagan1984
11,769votes
43.0% of the vote · D+13.2 · modeled estimate
Runner-up · Gerald Ford, 1976 · 11,310 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
Michael Dukakis1988
+34.9pts D vs U.S.
Place D+27.2 · U.S. R+7.7 · modeled estimate
Runner-up · Walter Mondale, 1984 · +31.4 pts
Republican
Warren G. Harding1920
+22.1pts R vs U.S.
Place R+48.3 · U.S. R+26.2 · modeled estimate
Runner-up · Calvin Coolidge, 1924 · +19.3 pts
current representation
Current officeholders
DBill DotzlerState Senate · 31
State legislative officeholder from OpenStates nightly current-legislator data.
U.S. House elections · 2 House
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.
Source · Akashic county-allocated estimate from certified county returns, House; not precinct-counted.
Year
Vote lead
Democratic
Republican
Total
2020
D
55.1%17,695
44.9%14,394
32,089
2018
D
57.3%14,558
42.7%10,846
25,404
Iowa Senate District 31 leans heavily Republican in statewide contests, with its largely rural and small-town electorate delivering some of the state's more consistent margins. Demographic shifts here have trended toward consolidating that alignment over the past decade.
Across the recorded series it reached a Democratic high of 35.5 points in 2008 and a Republican high of 48.3 points in 1920. Between 2020 and 2024 the district moved 9.5 points toward the Republican candidate; the 2024 margin was 12.3 points.
A population of 64,306, a 65% non-Hispanic-white share, and a median household income of $56,662 describe the district. The district's voting pattern over the last decade is most similar to that of State Senate District 39 and State Senate District 49.
Akashic
Political twins — state-senate districts
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.
Compare two places, side by side
Twelve curated comparisons line up election history, demographics, and the divergence story for two places at a glance. Browse all comparisons → · Or open the source-auditable district brief for electoral baseline, electorate, current-cycle coverage, geography, official dates, and methodology. Open campaign intelligence report →
Cite this page
All citations released under CC BY 4.0. Attribution: Akashic Intelligence.
Iowa 31st State Senate District. Akashic. https://akashic.app/sld-upper/19031/. Accessed May 20, 2026. License: CC BY 4.0.
How did Iowa 31st State Senate District vote in 2024?
In 2024, Iowa 31st State Senate District voted Democratic by 12.3 points (D+12.3), carried by the Democratic candidate. Out of 25,232 votes cast, 13,964 went Democratic and 10,859 went Republican.
When did Iowa 31st State Senate District last vote Republican?
The most recent presidential election in which Iowa 31st State Senate District voted Republican was 1972.
How many people live in Iowa 31st State Senate District?
Iowa 31st State Senate District has a population of 64,306 according to the 2024 American Community Survey 5-year estimates from the US Census Bureau.
What is the median household income in Iowa 31st State Senate District?
Median household income in Iowa 31st State Senate District is $56,662 — below the national median of $80,734. The Iowa state median is $75,059.
What is the political history of Iowa 31st State Senate District?
Akashic tracks 38 presidential elections in Iowa 31st State Senate District from 1876 to 2024. Of those, 22 went Democratic and 15 went Republican.