Cottleville is a city in St. Charles County, Missouri, United States.

The town was first settled by Captain Warren G. Cottle in 1798 under a Spanish land grant.

His son, Lorenzo, inherited 200 acres on both sides of the Dardenne River and, in 1839, parceled and named the town Cottleville after his father and grandfather.

Early settlers included George Huffman (before 1803), Aaron Rutger (before 1809), Nathaniel Simons, and Nicholas Contz.

According to the United States Census Bureau, the city has a total area of 4.46 square miles (11.55 km2), all land.

There were 1,145 housing units at an average density of 256.7 per square mile (99.1/km2).

13.3% of all households were made up of individuals, and 3.6% had someone living alone who was 65 years of age or older.

8.2% of all households were made up of individuals, and 2.2% had someone living alone who was 65 years of age or older.