Iowa has closed caucuses. Voters must be registered with a party in order to attend that party’s caucus. The two parties have different caucus formats, with one of the key differences being that Republicans vote by secret ballot.  Democrats will be able to mail-in presidential preference ballots starting in 2024. Iowa Democrats will be able to register for the mail in process starting November 1, 2023. Presidential preference cards will be mailed starting January 12, 2024. Iowa Democrats will hold their in-person precinct caucuses January 15, 2024. The last day to request a presidential preference card is February 19, 2024. The Iowa Democratic Party will release results of its 2024 mail-in caucus presidential preference on March 5, 2024. Iowa Democrats will accept presidential preference cards postmarked on or before March 5, 2024. To update your registration, submit a new voter registration online or send a paper form to your county auditor.