The Colorado Secretary of State's complete 2018 Election Calendar
may be found here
January 8, 2018 - Last day to affiliate with the Republican Party or Democratic Party in order to vote in their March 6th Party precinct caucuses
February 5, 2018 - Last day to change your voter registration address in order to reside in the precinct for 30 days, a requirement to vote in a specific precinct for the March 6th Party precinct caucuses
March 6, 2018 - Republican Party and Democratic Party Precinct Caucus Day
May 8, 2018 - Special Districts Election Day. All Ballots Must Be Received by 7:00 p.m.
May 29, 2018 - Deadline to Change or Withdraw Party Affiliation for Primary Election
June 4-8, 2018 - Primary Ballots Mailed to Democratic, Republican and Unaffiliated Voters
June 4, 2018 - Twenty Four Hour Primary Ballot Drop-off Locations Open
June 18, 2018 - Last Day to Register to Vote In Order or Request to Receive Primary Ballot by Mail.
June 18, 2018 - Voter Service and Polling Centers Open for the Primary Election
June 19, 2018 - Last Day to Return Primary Ballot by Mail
June 26, 2018 - Primary Election Day. All Ballots Must Be Received by 7:00 p.m.
July 5, 2018 - Overseas and Military Voters Must Send Primary Ballots So That They're Received by 7:00 p.m.
July 5, 2018 - Deadline to Cure Primary Ballot Signature or ID Issue
July 9, 2018 - Deadline For Election Officials to Canvass (Certify) Election Results
August 6, 2018 - Deadline to file an initiative petition with the Secretary of State for the 2018 General Election
September 10, 2018 - Candidate list becomes official and candidates are certified to the general election ballot
September 22, 2018 - Last Day to Send Ballots to Overseas and Military Voters
October 15, 2018 - Last Day to Register to Vote as Part of a Registration Drive
October 15, 2018 - Ballots Mailed to Voters During This Week (should arrive by October 19)
October 22, 2016 - Minimum Number of Voter Service and Polling Centers Open During This Week
November 3, 2018 - Ballot Drop Off Locations Open During This Week
November 6, 2018 - General Election hours 7:00 a.m. - 7:00 p.m. All Ballots Must Be Received by 7:00 p.m.
November 6, 2018 - Overseas and Military Voters Must Send Ballots by 7:00 p.m. Ballots Must Be Received by 8 Days After Election
You may also register to vote and vote on election day