Voting in Colorado

Who may vote

Article VII, Section 1: "Only a citizen of the United States who has attained the age of eighteen years, has resided in this state for such time as may be prescribed by law, and has been duly registered as a voter if required by law shall be qualified to vote at all elections." By statute (C.R.S. 1-2-101), you must have resided in Colorado for at least 22 days before the election. Article II, Section 5 requires that "all elections shall be free and open."

Registering

• Register or update your registration online at GoVoteColorado.gov, run by the Colorado Secretary of State.
• To have a ballot mailed to you, register or update your registration through the 8th day before Election Day. After that, you can still register and vote in person at a voter service and polling center in your county through Election Day.
• If you are unaffiliated, you may vote in one major party's primary. Unless you choose a ballot preference in advance, you are mailed each major party's ballot; vote and return only one, or none of your votes will count.

Your mail ballot

County clerks mail a ballot to every active registered voter 18 to 22 days before an election (C.R.S. 1-7.5-107).

1. Read the Blue Book, the ballot information booklet for statewide measures that the legislature's nonpartisan research staff (Legislative Council) distributes to active registered voters at least 30 days before the election. It includes the major arguments for and against each measure (Article V, Section 1(7.5)).
2. Mark the ballot, sign the envelope (your signature is checked against your record), and return it. If you recently registered for the first time, you may need to include a copy of your ID.
3. Ballots must be received by the county clerk by 7 p.m. on Election Day. Postmarks do not count. Use an official drop box if it is close to the deadline. (Military and overseas voters under federal UOCAVA rules have a later receipt deadline; see the Secretary of State's military and overseas page.)
4. Track your ballot from sent to accepted by signing up for BallotTrax.

Voting in person

If you vote in person at a voter service and polling center, you must show identification; most voters bring a Colorado driver's license or Colorado ID card. Anyone in line by 7 p.m. on Election Day may vote.

Why it matters

Colorado voters decide not only candidates but also constitutional amendments and laws placed on the ballot by petition (next lessons), and tax increases under the Taxpayer's Bill of Rights. An informed vote on a ballot measure is as important as a vote for a candidate. Colorado's men gave women the vote by referendum in 1893, the first state to do so by popular vote.

Election rules change. Confirm deadlines and requirements with the Colorado Secretary of State or your county clerk and recorder.

Sources: Colorado Secretary of State, Voter Registration FAQs, Mail Ballot FAQs, Primary Elections FAQs and Election Day FAQs (checked November 2026).