St. Louis County

St. Louis County is an administrative area in Missouri that wraps around the southern and western sides of the city of St. Louis, covering several smaller towns and wooded areas along the Mississippi River. The landscape alternates between densely built residential neighborhoods, commercial zones, and green park spaces that give the area a suburban character.

The area formed during the westward expansion of the United States and became officially part of Missouri Territory after the French colonial period. Later, the region developed into a center for trade and industry, with many European immigrants establishing new settlements here.

The name connects the region directly to French history and King Louis IX, whose legacy remains visible in street names and public buildings today. Visitors notice the mix of older brick neighborhoods and modern suburbs, where families use parks and shopping centers.

Travelers find many crossroads of major highways here, which simplify orientation and trips toward nearby cities and attractions. Public transport connects some neighborhoods, but a vehicle makes access to more remote destinations much easier.

The boundary between the area and the city of St. Louis runs partly through built-up streets, so visitors sometimes cross from one administrative zone to another without noticing. This division dates back to a decision in the 19th century, when both territories were organized separately.

Location: Missouri

Inception: 1812

Capital city: Clayton

Shares border with: St. Charles County, St. Louis, Jefferson County, Madison County, Franklin County, St. Clair County, Monroe County

Website: https://stlouiscountymo.gov

GPS coordinates: 38.64000,-90.44000

Latest update: December 4, 2025 23:00