Location: Braddock, Allegheny County
Dates of Operation: 1875 to Present
Owners: Carnegie, McCandless and Company; Carnegie Steel Company; United States Steel Corporation
Historical Significance: The Edgar Thomson Works was Andrew Carnegie’s first steel mill and was the first large Bessemer steel plant in the area. Today, United States Steel continues to operate the works, which is the lone plant in Pennsylvania engaged in only basic steelmaking.