U.S. Steel Edgar Thomson Works, Along Monongahela River, Braddock, Allegheny County, PA

Significance: Named after the president of the Pennsylvania Railroad and early financial backer of the enterprises, was the first integrated Bessener steel works constructed in the Pittsburgh district by Andrew Carnegie. Built primarily as a rail manufacturing facility, ET was the prototype of modern steel mill technology, design, and management. ET began an industrial transformation of the Monongahela Valley from a production center of scattered iron works to an integrated steel manufacturing district. ET continues to produce steel today.
Survey number: HAER PA-384
Building/structure dates: 1873- 1875 Initial Construction
Building/structure dates: 1912 Subsequent Work
Building/structure dates: 1941-1943 Subsequent Work
Building/structure dates: 1972 Subsequent Work