Voter file loaded July 20, 2026 · figures are from that file, held as a fixed record
Madison County, Idaho has 21,237 active registered voters — 72.9% Republican, 4.4% Democratic, and 21.1% with no party affiliation, as of July 2026.
Party registration
Most reliable-voting precincts
| # | Precinct | Active voters | Supervoters | Supervoter % |
|---|---|---|---|---|
| 1 | 019 | 802 | 409 | 51.0% |
| 2 | 004 | 590 | 275 | 46.61% |
| 3 | 018 | 924 | 381 | 41.23% |
| 4 | 016 | 1,150 | 460 | 40.0% |
| 5 | 003 | 1,707 | 669 | 39.19% |
| 6 | 006 | 1,394 | 527 | 37.8% |
| 7 | 002 | 1,906 | 705 | 36.99% |
| 8 | 005 | 1,086 | 334 | 30.76% |
| 9 | 014 | 1,065 | 324 | 30.42% |
| 10 | 007 | 1,631 | 476 | 29.18% |
Supervoters are active registered voters who cast a ballot in at least 3 of the last 4 November general elections (2018–2024). Percentages are precinct totals from the official state voter file — no individual voter information is shown. Precincts with fewer than 400 active voters are excluded.
How Madison County voted for president
Election results are public records.
Madison County at a glance.
Madison County had an estimated 55,549 residents in July 2024, the seventh most populous of Idaho's 44 counties, up 5.0% since the 2020 census. Of those, 44,118 are 18 or older, the voting-age population, and 5.7% are 65 or older. Its 21,237 active registered voters equal about 48.1% of that voting-age population.
It covers 469 square miles of land (118 people per square mile), and 22.4% of residents live outside any incorporated city or town. The largest cities and towns are Rexburg (40,695) and Sugar City (2,395). The American Community Survey (2020-2024) puts it at a median age of 21.4, a median household income of $60,160, 41.8% of adults 25 and older holding a bachelor's degree or higher and 40.2% of occupied homes owned by the people living in them.
In 2024, 17,358 votes were cast for president, about 39.3% of the voting-age population; the Democratic ticket took 15.9% and the Republican ticket 80.2%. The two-party margin moved from R+72.7 in 2008 to R+64.3 in 2024.
- Population (2024 estimate)
- 55,549
- Population (2020 census base)
- 52,911
- Voting-age population (18+)
- 44,118
- Active voters per 100 adults
- 48.1
- Residents 65 and older
- 5.7%
- People per square mile
- 118
- Living outside incorporated places
- 22.4%
- Land area
- 469 sq mi
- Median age
- 21.4
- Median household income
- $60,160
- Adults 25+ with a bachelor's degree
- 41.8%
- Owner-occupied homes
- 40.2%
Largest cities and towns
- Rexburg 40,695
- Sugar City 2,395
Presidential vote, 2008–2024
| Year | Democratic | Republican | Margin | Votes cast |
|---|---|---|---|---|
| 2024 | 15.9% | 80.2% | R+64.3 | 17,358 |
| 2020 | 15.6% | 79.2% | R+63.6 | 17,112 |
| 2016 | 7.7% | 57.0% | R+49.3 | 15,687 |
| 2012 | 5.8% | 93.3% | R+87.5 | 14,412 |
| 2008 | 12.5% | 85.2% | R+72.7 | 13,057 |
Sources: U.S. Census Bureau Vintage 2024 population estimates and 2024 Gazetteer; American Community Survey 2020–2024 5-year estimates; certified county presidential returns. Growth, density and turnout are simple arithmetic on those figures.
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