Williamstown is a city in Wood County, West Virginia, United States, along the Ohio River. It is part of the Parkersburg–Vienna metropolitan area. The population was 2,997 at the 2020 census. The now closed Fenton Art Glass Company was located in the city.

Wood County is a county in the U.S. state of West Virginia. As of the 2020 census, the population was 84,296, making it West Virginia's fifth-most populous county. Its county seat is Parkersburg. The county was formed in 1798 from the western part of Harrison County and named for James Wood, governor of Virginia from 1796 to 1799.