Colorado

Find nonpartisan voter education and local coverage for Colorado. A summary of Colorado voting rules is below, and each county on the map has its own page.

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All 64 Colorado counties (A–Z)

Voting in Colorado

Voting rules are set by each state. This is a summary of Colorado voting rules, checked Nov. 4, 2026, from Vote.gov (U.S. government), the National Conference of State Legislatures (NCSL) and Ballotpedia. Rules and dates can change, so confirm with Colorado’s official election website or your local election office before each election.

Registering to vote

Online: by 8 days before Election Day.
By mail: must be postmarked 8 days before Election Day.
In person: available through Election Day (same-day registration).
Register or check your registration (Colorado on Vote.gov)

Primary elections

Colorado has semi-closed primaries: voters registered with a party vote in that party’s primary, and unaffiliated voters may choose one party’s primary.

Voter ID

Colorado asks voters to show an ID, and non-photo IDs are accepted. If you don’t have one, there are other ways to cast a ballot that counts, depending on state rules.

Early voting

Starts: Voter service and polling centers must be open 15 days before an election. Note: Colorado conducts elections primarily by mail. Ends: Day of election. Locations and hours are set locally.

Voting by mail

Colorado conducts elections by mail: registered voters are automatically sent a ballot. You can still vote in person.

Your local election office

Find contact information for your local election office on Colorado’s official election website.

Sources: Vote.gov (registration deadlines); NCSL voter ID (updated Sept. 3, 2026), early voting (updated Aug. 11, 2026) and absentee voting (updated July 17, 2026); Ballotpedia primary types (as of Aug. 2026).