Data as of November 4, 2026 · refreshed automatically from the official Colorado voter file
Arapahoe County, CO has 420,976 active registered voters — 18.6% Republican, 28.1% Democratic, and 50.8% with no party affiliation, as of November 2026.
Party registration
Most reliable-voting precincts
| # | Precinct | Active voters | Supervoters | Supervoter % |
|---|---|---|---|---|
| 1 | 6294103443 | 524 | 401 | 76.53% |
| 2 | 6276103215 | 1,425 | 1,088 | 76.35% |
| 3 | 6294103440 | 813 | 608 | 74.78% |
| 4 | 6294103441 | 809 | 593 | 73.3% |
| 5 | 6163803196 | 653 | 474 | 72.59% |
| 6 | 6163803186 | 927 | 668 | 72.06% |
| 7 | 6163803156 | 1,158 | 821 | 70.9% |
| 8 | 6163803168 | 969 | 685 | 70.69% |
| 9 | 6263703203 | 723 | 511 | 70.68% |
| 10 | 6163703221 | 818 | 578 | 70.66% |
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 Arapahoe County voted for president
Election results are public records.
Arapahoe County at a glance.
Arapahoe County had an estimated 666,918 residents in July 2024, the third most populous of Colorado's 64 counties, up 1.8% since the 2020 census. Of those, 519,891 are 18 or older, the voting-age population, and 15.2% are 65 or older. Its 420,976 active registered voters equal about 81.0% of that voting-age population.
It covers 798 square miles of land (836 people per square mile), and 15.4% of residents live outside any incorporated city or town. The largest cities and towns are Aurora (part) (341,313), Centennial (108,853), Littleton (part) (42,044), Englewood (35,238) and Greenwood Village (15,288). The American Community Survey (2020-2024) puts it at a median age of 37.3, a median household income of $101,087, 46.5% of adults 25 and older holding a bachelor's degree or higher and 64.7% of occupied homes owned by the people living in them.
In 2024, 325,451 votes were cast for president, about 62.6% of the voting-age population; the Democratic ticket took 58.6% and the Republican ticket 38.5%. The two-party margin moved from D+12.9 in 2008 to D+20.1 in 2024.
- Population (2024 estimate)
- 666,918
- Population (2020 census base)
- 655,077
- Voting-age population (18+)
- 519,891
- Active voters per 100 adults
- 81.0
- Residents 65 and older
- 15.2%
- People per square mile
- 836
- Living outside incorporated places
- 15.4%
- Land area
- 798 sq mi
- Median age
- 37.3
- Median household income
- $101,087
- Adults 25+ with a bachelor's degree
- 46.5%
- Owner-occupied homes
- 64.7%
Largest cities and towns
- Aurora (part) 341,313
- Centennial 108,853
- Littleton (part) 42,044
- Englewood 35,238
- Greenwood Village 15,288
Presidential vote, 2008–2024
| Year | Democratic | Republican | Margin | Votes cast |
|---|---|---|---|---|
| 2024 | 58.6% | 38.5% | D+20.1 | 325,451 |
| 2020 | 61.0% | 36.4% | D+24.6 | 350,183 |
| 2016 | 52.7% | 38.9% | D+13.8 | 281,658 |
| 2012 | 53.2% | 44.8% | D+8.4 | 254,746 |
| 2008 | 55.7% | 42.8% | D+12.9 | 266,148 |
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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