Voter file loaded July 20, 2026 · figures are from that file, held as a fixed record
Ada County, Idaho has 301,507 active registered voters — 52.8% Republican, 17.6% Democratic, and 28.2% with no party affiliation, as of July 2026.
Party registration
Most reliable-voting precincts
| # | Precinct | Active voters | Supervoters | Supervoter % |
|---|---|---|---|---|
| 1 | 1812 | 1,417 | 942 | 66.48% |
| 2 | 1807 | 1,522 | 1,004 | 65.97% |
| 3 | 1923 | 1,464 | 949 | 64.82% |
| 4 | 1903 | 1,486 | 944 | 63.53% |
| 5 | 1504 | 1,484 | 942 | 63.48% |
| 6 | 1509 | 1,521 | 961 | 63.18% |
| 7 | 2208 | 1,438 | 906 | 63.0% |
| 8 | 1905 | 1,857 | 1,167 | 62.84% |
| 9 | 1811 | 1,416 | 888 | 62.71% |
| 10 | 1810 | 1,533 | 957 | 62.43% |
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 Ada County voted for president
Election results are public records.
Ada County at a glance.
Ada County had an estimated 535,799 residents in July 2024, the most populous of Idaho's 44 counties, up 8.2% since the 2020 census. Of those, 422,901 are 18 or older, the voting-age population, and 17.3% are 65 or older. Its 301,507 active registered voters equal about 71.3% of that voting-age population.
It covers 1,052 square miles of land (509 people per square mile), and 12.0% of residents live outside any incorporated city or town. The largest cities and towns are Boise City (237,963), Meridian (139,740), Eagle (33,451), Kuna (29,127) and Star (part) (18,155). The American Community Survey (2020-2024) puts it at a median age of 38.4, a median household income of $91,502, 44.6% of adults 25 and older holding a bachelor's degree or higher and 70.8% of occupied homes owned by the people living in them.
In 2024, 267,340 votes were cast for president, about 63.2% of the voting-age population; the Democratic ticket took 43.4% and the Republican ticket 53.8%. The two-party margin moved from R+6.2 in 2008 to R+10.4 in 2024.
- Population (2024 estimate)
- 535,799
- Population (2020 census base)
- 494,969
- Voting-age population (18+)
- 422,901
- Active voters per 100 adults
- 71.3
- Residents 65 and older
- 17.3%
- People per square mile
- 509
- Living outside incorporated places
- 12.0%
- Land area
- 1,052 sq mi
- Median age
- 38.4
- Median household income
- $91,502
- Adults 25+ with a bachelor's degree
- 44.6%
- Owner-occupied homes
- 70.8%
Largest cities and towns
- Boise City 237,963
- Meridian 139,740
- Eagle 33,451
- Kuna 29,127
- Star (part) 18,155
Presidential vote, 2008–2024
| Year | Democratic | Republican | Margin | Votes cast |
|---|---|---|---|---|
| 2024 | 43.4% | 53.8% | R+10.4 | 267,340 |
| 2020 | 46.5% | 50.4% | R+3.9 | 259,389 |
| 2016 | 38.7% | 47.9% | R+9.2 | 195,587 |
| 2012 | 42.7% | 54.0% | R+11.3 | 180,361 |
| 2008 | 45.8% | 52.0% | R+6.2 | 179,402 |
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.
Running in Ada County?
The voter file is loaded. Create your campaign and start canvassing in minutes.
Start free in Ada CountyAlso see: Motion51 in Idaho · How to run for office in Ada County · Pricing