227,495
Active registered voters
192
Precincts
139,224
Supervoters (61.2%)
5
Presidential cycles of results
Data as of September 22, 2026 · refreshed automatically from the official Colorado voter file
Boulder County, CO has 227,495 active registered voters — 9.8% Republican, 37.9% Democratic, and 50.4% with no party affiliation, as of September 2026.
Party registration
Democratic 86,140 · Republican 22,398 · No Party Affiliation 114,607 · Other parties 4,350
Source: Motion51 voter database — official Colorado voter file
Most reliable-voting precincts
| # | Precinct | Active voters | Supervoters | Supervoter % |
|---|---|---|---|---|
| 1 | 2171907407 | 458 | 350 | 76.42% |
| 2 | 2181207506 | 1,459 | 1,109 | 76.01% |
| 3 | 2151207700 | 1,284 | 968 | 75.39% |
| 4 | 2181207509 | 1,517 | 1,142 | 75.28% |
| 5 | 2181207508 | 1,520 | 1,142 | 75.13% |
| 6 | 2171107627 | 975 | 731 | 74.97% |
| 7 | 2181207500 | 1,248 | 932 | 74.68% |
| 8 | 2181207502 | 1,451 | 1,083 | 74.64% |
| 9 | 2171207316 | 1,354 | 1,010 | 74.59% |
| 10 | 2181007802 | 1,126 | 839 | 74.51% |
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.
Source: Motion51 voter database — official Colorado voter file
How Boulder County voted for president
■ Democratic % ■ Republican % · 2024 total votes cast: 196,150
Election results are public records.
Source: Official county canvasses via MIT Election Data + Science Lab
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