Missouri

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

Explore Missouri Counties

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All 115 Missouri counties (A–Z)

Voting in Missouri

Voting rules are set by each state. This is a summary of Missouri 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 Missouri’s official election website or your local election office before each election.

Registering to vote

Online: by 27 days before Election Day.
By mail: must be postmarked 27 days before Election Day.
In person: by 27 days before Election Day.
Register or check your registration (Missouri on Vote.gov)

Primary elections

Missouri has open primaries: there is no party registration, and on primary day you choose one party’s ballot. You can vote in only one party’s primary.

Voter ID

Missouri asks voters to show a photo ID. If you don’t have one, there are other ways to cast a ballot that counts, such as being identified by a poll worker or signing an affidavit, depending on state rules.

Early voting

Starts: The second Tuesday before an election (in-person absentee). Ends: Not specified. Locations and hours are set locally.

Voting by mail

Missouri requires an approved reason (excuse) to vote by absentee/mail ballot. Check the state’s list of qualifying reasons.

Your local election office

Find contact information for your local election office on Missouri’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).