Clairton is a city in Allegheny County, Pennsylvania, United States, along the Monongahela River. It is part of the Pittsburgh Metropolitan Area. The population was 6,796 at the 2010 census. Under Pennsylvania legal classifications for local governments, Clairton is considered a third-class city. It is home to Clairton Works, the largest coke manufacturing facility in the United States.
The city was the setting for the movie The Deer Hunter (1978), although none of the movie was actually filmed there (other mill towns in the Monongahela River Valley and elsewhere in the tri-state area were used). Even the opening scene, which features a large sign saying "Welcome to Clairton, City of Prayer," was shot in Mingo Junction, Ohio, although its phrasing is based on smaller signs posted at the city's boundaries during the mid-1960s (as a response to the Supreme Court's 1963 ban on sponsored school prayer).
The Montour Trail, a recreational rail-trail, extends from Clairton to Coraopolis, Pennsylvania.
Clairton is located at 40°17′47″N 79°53′14″W (40.296419, -79.887090).
According to the United States Census Bureau, the city has a total area of 3.0 square miles (7.8 km2). 2.8 square miles (7.3 km2) of it is land, and 0.2 square miles (0.52 km2) of it (8.31%) is water.