St. Marys is a city in and the county seat of Pleasants County, West Virginia, United States. The population was 1,847 at the 2020 census. It is part of the Parkersburg–Vienna metropolitan area. 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.