St. Louis Metro Area Counties

15 counties · 2.8 million people (2025) · 7,863 sq mi

The St. Louis metro area (officially the St. Louis, MO-IL Metropolitan Statistical Area) has 15 counties in Illinois and Missouri, with 2,814,421 people in 2025. St. Louis County is the most populous.

Map of the 15 counties of the St. Louis metro area with county names and major cities
The 15 counties of the St. Louis metro area (yellow) with the largest cities. Boundaries: U.S. Census Bureau, 2025. Free to use with attribution (CC BY 4.0).
PDF (Letter) 293 KBPNG (2400 px) 149 KB

The 15 counties of the St. Louis metro area

Sorted by population. 7 are central counties (the urban core); the others are outlying counties tied to it by commuting.

CountyStateCounty seatPopulation 2025Change since 2020Land area (sq mi)Type
St. Louis CountyMissouriClayton990,911−1.4%509Central
St. Charles CountyMissouriSt. Charles426,499+5.2%560Central
St. Louis cityMissouriSt. Louis278,144−7.7%62Central
Madison CountyIllinoisEdwardsville263,110−1.1%716Central
St. Clair CountyIllinoisBelleville250,708−2.7%658Central
Jefferson CountyMissouriHillsboro233,132+2.9%656Central
Franklin CountyMissouriUnion108,090+3.3%923Outlying
Lincoln CountyMissouriTroy66,676+11.9%627Outlying
Macoupin CountyIllinoisCarlinville43,748−2.9%863Outlying
Warren CountyMissouriWarrenton39,016+9.8%429Outlying
Clinton CountyIllinoisCarlyle37,128+0.6%474Outlying
Monroe CountyIllinoisWaterloo34,840−0.3%385Central
Jersey CountyIllinoisJerseyville21,160−1.7%370Outlying
Bond CountyIllinoisGreenville16,959+0.4%380Outlying
Calhoun CountyIllinoisHardin4,300−2.9%254Outlying

The metro area is part of the larger St. Louis-St. Charles-Farmington, MO-IL Combined Statistical Area.

Printable map

The PDF is a vector file for Letter paper; the PNG is 2400 pixels wide. Both are free to use with a credit to WhichCounty.

County maps of Illinois and Missouri

Other metro areas

Sources