Missouri Counties Directory & Interactive Map
Complete official guide to all 115 counties in Missouri (MO). Explore 2024 US Census population estimates, county seats, FIPS codes, land areas, and interactive mapping tools powered by GeoMap Suite.
Missouri County Breakdown
Showing 9 of 9 documented counties and seats.
County Name | FIPS | County Seat | Population (Census) | Land Area | Quick Tool |
|---|---|---|---|---|---|
| St. Louis County | 29189 | Clayton | 1,004,125 | 508 sq mi | Lookup |
| Jackson County (Kansas City) | 29095 | Kansas City / Independence | 717,204 | 605 sq mi | Lookup |
| St. Charles County | 29183 | Saint Charles | 405,262 | 561 sq mi | Lookup |
| St. Louis City (Independent) | 29510 | St. Louis | 301,578 | 62 sq mi | Lookup |
| Greene County (Springfield) | 29077 | Springfield | 298,915 | 675 sq mi | Lookup |
| Clay County | 29047 | Liberty | 253,335 | 397 sq mi | Lookup |
| Jefferson County | 29099 | Hillsboro | 226,739 | 657 sq mi | Lookup |
| Boone County (Columbia) | 29019 | Columbia | 183,615 | 685 sq mi | Lookup |
| Cole County (Jefferson City) | 29051 | Jefferson City | 77,279 | 392 sq mi | Lookup |
Geographic Structure of Missouri Counties
County Administration & Governance
In Missouri, county governments manage vital public infrastructure, tax assessments, law enforcement, judicial courts, election administration, and public records. The county seat (Clayton and other municipal headquarters) houses the primary courthouse, commissioners, and sheriff’s department.
All Missouri counties carry a unique 5-digit Federal Information Processing Standard (FIPS) code, where the first two digits (29) designate the state and the remaining three digits identify each specific jurisdiction.
Geographic & Demographic Highlights
- Most Populous County:St. Louis County (1,004,125 residents)
- Largest by Land Area:Boone County (Columbia) (685 sq mi)
- State Capital:Jefferson City
- Census Bureau Region:Midwest United States
Demographic calculations derive from the United States Census Bureau 2024 Population Estimates Program (PEP) and TIGER/Line geographic boundary files.