St. Marys is a city in Pleasants County, West Virginia, in the United States. The population was 1,860 at the 2010 census. It is the county seat of Pleasants County. St. Marys was established in 1849 by Alexander Creel, who is said to have had a vision of Mary while passing the townsite by boat on the Ohio River.
Train tracks run down the middle of 2nd Street in St. Marys, and freight trains running through the middle of downtown St. Marys are a common sight. It is one of the few towns in the United States where freight trains actually share city streets with automotive traffic.