Vandalia is a city in Audrain and Ralls Counties in the U.S. state of Missouri. The population was 3,899 at the 2010 census, which includes about 2000 prisoners incarcerated at the Prison located within the City Limits.
Col. Aaron McPike, who founded Vandalia in 1874, called Vandalia "Queen of the Prairie". It was named after Vandalia, Illinois. Vast rolling prairies had underlying coal and refractory types of clay. Brickplants are major employers in Audrain County today.