Voter file loaded July 20, 2026 · figures are from that file, held as a fixed record
Custer County, Idaho has 3,011 active registered voters — 79.7% Republican, 4.7% Democratic, and 15.0% with no party affiliation, as of July 2026.
Party registration
Most reliable-voting precincts
| # | Precinct | Active voters | Supervoters | Supervoter % |
|---|---|---|---|---|
| 1 | 003 | 551 | 343 | 62.25% |
| 2 | 004 | 415 | 256 | 61.69% |
| 3 | 006 | 506 | 276 | 54.55% |
| 4 | 001 | 620 | 300 | 48.39% |
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 Custer County voted for president
Election results are public records.
Custer County at a glance.
Custer County had an estimated 4,597 residents in July 2024, the 40th most populous of Idaho's 44 counties, up 7.5% since the 2020 census. Of those, 3,817 are 18 or older, the voting-age population, and 32.5% are 65 or older. Its 3,011 active registered voters equal about 78.9% of that voting-age population.
It covers 4,922 square miles of land (0.9 people per square mile), and 66.1% of residents live outside any incorporated city or town. The largest cities and towns are Challis (944), Mackay (480), Stanley (122) and Clayton (12). The American Community Survey (2020-2024) puts it at a median age of 60.0, a median household income of $67,574, 29.3% of adults 25 and older holding a bachelor's degree or higher and 76.8% of occupied homes owned by the people living in them.
In 2024, 2,650 votes were cast for president, about 69.4% of the voting-age population; the Democratic ticket took 22.1% and the Republican ticket 75.4%. The two-party margin moved from R+46.0 in 2008 to R+53.3 in 2024.
- Population (2024 estimate)
- 4,597
- Population (2020 census base)
- 4,276
- Voting-age population (18+)
- 3,817
- Active voters per 100 adults
- 78.9
- Residents 65 and older
- 32.5%
- People per square mile
- 0.9
- Living outside incorporated places
- 66.1%
- Land area
- 4,922 sq mi
- Median age
- 60.0
- Median household income
- $67,574
- Adults 25+ with a bachelor's degree
- 29.3%
- Owner-occupied homes
- 76.8%
Largest cities and towns
- Challis 944
- Mackay 480
- Stanley 122
- Clayton 12
Presidential vote, 2008–2024
| Year | Democratic | Republican | Margin | Votes cast |
|---|---|---|---|---|
| 2024 | 22.1% | 75.4% | R+53.3 | 2,650 |
| 2020 | 22.0% | 76.3% | R+54.3 | 2,739 |
| 2016 | 17.7% | 73.6% | R+55.9 | 2,413 |
| 2012 | 22.5% | 74.1% | R+51.6 | 2,352 |
| 2008 | 26.0% | 72.0% | R+46.0 | 2,352 |
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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