Clairton is a city in Allegheny County, Pennsylvania, United States. It is located along the Monongahela River and is part of the Pittsburgh metropolitan area. The population was 6,181 at the 2020 census, and was estimated to be 5,945 in 2024. Under Pennsylvania legal classifications for local governments, Clairton is considered a third-class city. It is home to the Clairton Coke Works operated by U.S. Steel, the largest coke manufacturing facility in North America.