Edgar Thompson Steel Plant, Pennsylvania

A few miles up the Monongahela River from downtown Pittsburgh is U.S. Steel’s Edgar Thompson steel plant. The first steel works here were built in 1875 to produce rails for the Pennsylvania Railroad. This was Andrew Carnegie’s first large steel mill purchase, the beginning of his steel empire. It is still a major producer, and employs around 1,000 people. The plant makes 2.8 million tons of steel annually, the largest remaining producer in the Pittsburgh region. It is part of US Steel’s Mon Valley Works, a network that includes the Clairton Coke Works, and the nearby Irvin finishing plant.