Redistricting in St. Louis: History and Current Boundaries

Redistricting shapes which elected officials represent St. Louis residents, how political power is distributed across neighborhoods, and which communities share a legislative voice at the city, county, state, and federal levels. This page covers the definition and legal framework of redistricting as it applies to St. Louis City and St. Louis County, the procedural mechanics that govern each cycle, the scenarios that most commonly trigger boundary disputes, and the criteria that constrain where lines can and cannot be drawn. Understanding these boundaries matters for anyone engaged with St. Louis civic governance, from candidates filing for office to residents challenging maps in court.

Definition and scope

Redistricting is the process of redrawing the geographic boundaries of electoral districts to reflect population changes recorded in the decennial U.S. Census. In Missouri, redistricting obligations apply at four distinct levels: U.S. Congressional districts, Missouri General Assembly districts (both House and Senate), St. Louis County Council districts, and St. Louis City aldermanic wards.

St. Louis City and St. Louis County are governed by separate redistricting authorities because of the city's unique legal status. The St. Louis City-County separation, formalized by the Missouri Constitution of 1876, means the City of St. Louis is an independent city — not part of any county — and therefore conducts its own ward redistricting independently of county processes. St. Louis County, by contrast, operates under county charter provisions and redraws its 7 council districts following each Census.

Scope and coverage: This page addresses redistricting processes within the City of St. Louis and St. Louis County, Missouri. It does not cover redistricting in Illinois counties that are part of the broader St. Louis metropolitan statistical area (MSA), such as St. Clair or Madison counties. Missouri's state legislative redistricting processes are governed by the Missouri Apportionment Commission and fall outside the scope of municipal and county-level analysis presented here. Federal Congressional redistricting, administered by the Missouri General Assembly, is also not covered in depth.

How it works

Missouri's redistricting cycle follows a structured sequence triggered by the release of decennial Census data, typically delivered to states between March and August of a Census year.

St. Louis City aldermanic wards are redrawn under authority of the St. Louis Board of Aldermen. The city is divided into 28 wards, each represented by one alderman. Following the 2020 Census, a redistricting commission was convened to propose new ward boundaries. Under Missouri law and the St. Louis City Charter, the Board of Aldermen retains final approval authority over the ward map. Population equality across wards is the primary constitutional requirement: each ward must contain approximately the same number of residents, a standard derived from the Equal Protection Clause of the 14th Amendment and confirmed in Reynolds v. Sims, 377 U.S. 533 (1964).

St. Louis County Council districts are redrawn by the County Council itself, subject to the St. Louis County Charter. The 7-district map must satisfy the same one-person, one-vote standard. The St. Louis County Council holds public hearings before adopting a final plan.

The numbered steps in a typical St. Louis redistricting cycle are:

1. U.S. Census Bureau releases PL 94-171 redistricting data files to Missouri.
2. The relevant governing body (Board of Aldermen or County Council) appoints or activates a redistricting commission or committee.
3. Draft maps are developed using Census block-level population data.
4. Public comment periods are held, typically spanning 30 to 60 days depending on charter requirements.
5. The governing body votes to adopt a final map.
6. Adopted maps are filed with the Missouri Secretary of State and become effective for the next election cycle.

The St. Louis Election Authority then implements precinct assignments based on the adopted ward or district boundaries.

Common scenarios

Population shift between wards: The most routine redistricting trigger is unequal population growth. If one St. Louis ward gains 4,000 residents while an adjacent ward loses 2,000, the resulting deviation from equality requires boundary adjustment. The acceptable deviation threshold under federal case law is generally ±10% for state and local legislative districts, though tighter tolerances are applied when partisan intent is alleged.

Contested maps and litigation: Redistricting plans are subject to challenge under the Voting Rights Act of 1965 (52 U.S.C. § 10301), which prohibits maps that dilute the voting power of racial or language minority communities. St. Louis, with a population that was approximately 42% Black as of the 2020 Census (U.S. Census Bureau, 2020 Decennial Census), has seen redistricting decisions scrutinized under Section 2 of the Voting Rights Act.

Ward reduction proposals: Between the 2010 and 2020 Census cycles, St. Louis considered reducing the number of aldermanic wards from 28 to 14 as part of broader St. Louis City charter amendment discussions. A 2020 ballot measure passed, setting in motion the reduction to 14 wards effective with the 2023 elections — the most significant structural change to aldermanic representation in St. Louis in decades.

County municipal boundary changes: When municipalities in St. Louis County annex territory or when unincorporated areas are developed, district boundaries may require mid-cycle adjustments to maintain alignment between service delivery and representation.

Decision boundaries

Not all boundary-drawing choices are discretionary. Redistricting authorities in St. Louis operate within a layered set of legal constraints:

• Federal constitutional floor: One-person, one-vote equality (Reynolds v. Sims) is non-negotiable.
• Voting Rights Act compliance: Maps cannot be drawn to dilute minority voting strength (52 U.S.C. § 10301).
• Missouri constitutional requirements: Article III of the Missouri Constitution governs state legislative apportionment; local charters govern city and county maps.
• Contiguity and compactness: Districts must be contiguous (no disconnected pieces) and reasonably compact, though neither standard is defined by precise mathematical formula in Missouri statutes.
• Community of interest preservation: Both the St. Louis City Charter and standard redistricting practice recognize that neighborhoods with shared economic, cultural, or civic ties should not be arbitrarily split.

The contrast between city ward redistricting and county district redistricting is significant in practice. City wards are smaller geographic units — St. Louis City covers only 66 square miles — so ward boundaries shift in relatively dense urban blocks. County council districts cover a geographically larger area, approximately 524 square miles, meaning boundary adjustments involve suburban and semi-rural tracts with very different demographic dynamics.

Disputes that cannot be resolved through the legislative process are adjudicated in Missouri circuit courts or in federal district court, depending on whether the claim is rooted in state charter provisions or federal constitutional and statutory rights. The St. Louis Circuit Court has jurisdiction over state-law redistricting challenges within the city.

References

• U.S. Census Bureau — PL 94-171 Redistricting Data
• U.S. Census Bureau — 2020 Decennial Census, City of St. Louis Profile
• 52 U.S.C. § 10301 — Voting Rights Act, Section 2 (U.S. House Office of the Law Revision Counsel)
• Missouri Secretary of State — Missouri Constitution, Article III
• St. Louis City Charter (St. Louis City Government)
• St. Louis Board of Aldermen
• St. Louis County Charter (St. Louis County Government)
• Reynolds v. Sims, 377 U.S. 533 (1964) (Justia)