Voter Registration in St. Louis City and County

Voter registration in St. Louis operates under a bifurcated administrative structure reflecting the unique separation between St. Louis City and St. Louis County — two distinct jurisdictions that share a name but function under entirely separate election authorities. This page covers the definition and legal scope of voter registration in the metro area, the mechanics of how registration is processed and maintained, the most common registration scenarios residents encounter, and the decision boundaries that determine which authority governs a given voter. Understanding which jurisdiction administers registration is a prerequisite for casting a valid ballot in any St. Louis-area election.

Definition and scope

Voter registration in Missouri is governed by Chapter 115 of the Missouri Revised Statutes (RSMo Chapter 115), which establishes eligibility requirements, registration deadlines, and the duties of local election authorities. At the state level, the Missouri Secretary of State oversees election administration and maintains the Missouri Voter Registration System (MVRS), the centralized database used by all local election authorities statewide.

Within the St. Louis metro, two separate local election authorities administer voter registration:

• St. Louis City: The St. Louis City Election Authority — formally the St. Louis City Board of Election Commissioners — administers registration for all residents of the City of St. Louis.
• St. Louis County: The St. Louis County Board of Elections administers registration for residents of St. Louis County, which includes 88 incorporated municipalities plus unincorporated areas.

These two bodies operate independently. A registration filed with one authority has no effect in the other jurisdiction. This split is a direct consequence of the city-county separation that has defined the region's governance structure since 1876.

Scope and coverage limitations: This page covers voter registration as administered within St. Louis City and St. Louis County, Missouri. Registration in Illinois counties that form part of the broader St. Louis metro — including Madison, St. Clair, and Monroe counties — falls under Illinois election law and is not covered here. Federal overseas and military voter registration under the Uniformed and Overseas Citizens Absentee Voting Act (UOCAVA) applies to eligible residents of both St. Louis City and County but is administered in coordination with the respective local election authority, not independently. Registration disputes involving state-level intervention fall under the jurisdiction of the Missouri Secretary of State, not the local boards.

How it works

Missouri law sets the voter registration deadline at 28 days before an election (RSMo §115.135). Residents who miss that window cannot register in time for that election cycle but may register immediately afterward for future elections.

Registration can be completed through 4 primary channels:

1. Online: The Missouri Secretary of State's online portal accepts registrations for residents with a Missouri driver's license or state ID. Both St. Louis City and County registrations flow through this portal into the MVRS.
2. Paper form: The standard Missouri Voter Registration Application can be submitted by mail or in person to the applicable local election authority. The postmark or delivery date must fall on or before the 28-day deadline.
3. Motor voter (NVRA): Under the National Voter Registration Act of 1993 (52 U.S.C. §20501), Missouri residents may register when obtaining or renewing a driver's license at a Missouri Department of Revenue license office. The registration is automatically forwarded to the appropriate local election authority based on the address provided.
4. Automatic Voter Registration (AVR): Missouri does not currently operate a full automatic voter registration system as of the date of this writing; Missouri's motor voter process remains opt-in at the point of transaction.

Once submitted, the local election authority verifies eligibility — Missouri requires applicants to be U.S. citizens, Missouri residents, at least 17.5 years old at the time of registration (18 by election day), and not under a disqualifying felony sentence or adjudication of mental incapacity (RSMo §115.133). Approved registrations are entered into MVRS and assigned to the correct precinct based on the registrant's address.

Precinct assignment matters significantly in St. Louis City, where aldermanic wards define political geography. A voter's ward and precinct determine which candidates appear on their ballot in municipal elections.

Common scenarios

Change of address within the same jurisdiction: A St. Louis City resident who moves to a new address within the city must update their registration with the St. Louis City Election Authority. Under Missouri law, voters who move within the same county (or independent city) and fail to update may still cast a provisional ballot at their old precinct in certain circumstances, but updating the registration before the 28-day deadline eliminates this complication.

Moving from St. Louis County to St. Louis City (or vice versa): Because these are two separate election jurisdictions, a move across the city-county boundary requires re-registration with the new authority. A registration on file with St. Louis County is not automatically transferred to the St. Louis City Election Authority, and the voter will not appear in city poll books until the new registration is processed.

First-time registrants: First-time registrants who register by mail and cannot verify identity through the MVRS database may be required to present identification when voting for the first time, consistent with the Help America Vote Act of 2002 (52 U.S.C. §21001).

Voters in St. Louis County municipalities: St. Louis County contains 88 municipalities — including Clayton, Kirkwood, Florissant, and Ferguson — all administered under the single St. Louis County Board of Elections. There is no separate election authority for individual municipalities within the county. Residents of all county municipalities, as well as unincorporated areas of St. Louis County, register through the county board.

Inactive voter status: Missouri election authorities may mark a registration as "inactive" following returned mail or a period of non-voting. An inactive registrant remains eligible to vote but may need to confirm their address at the polling place. Inactive registrations are not removed from the rolls without further confirmation steps, consistent with the National Voter Registration Act's list-maintenance requirements.

Decision boundaries

The threshold question in any St. Louis voter registration scenario is address jurisdiction: which side of the city-county boundary does the voter's residence fall on?

A secondary boundary involves age: Missouri permits pre-registration for 17-year-olds who will be 18 by the date of the next general election (RSMo §115.135). A 17-year-old who pre-registers may vote in a primary election held before their 18th birthday only if they will be 18 by the subsequent general election.

The St. Louis redistricting process periodically redraws precinct boundaries within both jurisdictions, which can shift a voter's assigned polling place or alter which candidates appear on their ballot without any change to the voter's physical address. Redistricting cycles do not require re-registration, but voters should verify their precinct assignment after any redistricting event.

For a broader orientation to civic services and government functions across both St. Louis City and County, the St. Louis Metro Authority home page provides a structured overview of the region's institutional landscape.

References

• Missouri Secretary of State — Elections Division
• Missouri Revised Statutes, Chapter 115 — Election Laws
• Missouri Revised Statutes §115.133 — Voter Eligibility
• Missouri Revised Statutes §115.135 — Registration Deadlines and Pre-registration
• National Voter Registration Act of 1993, 52 U.S.C. §20501
• Help America Vote Act of 2002, 52 U.S.C. §21001
• St. Louis City Board of Election Commissioners
• St. Louis County Board of Elections