10/06/2026
This time 114 years ago, construction of the open-hearth furnaces at the Edgar Thomson Plant along the Monongahela River in Braddock, Pennsylvania, was captured on film.
Edgar Thomson became one of the foundational mills of Pittsburghâs steel industry when it opened in 1875 after two years of construction. By 1912, these photographs captured the plant in the midst of expansion â a steelmaking operation taking shape one beam, building, and furnace at a time.
More than a century later, the work continues on the very same ground.
The buildings, equipment, technology and end products have evolved dramatically, but the purpose remains remarkably familiar: transforming raw materials into steel. Today, Edgar Thomson is part of U. S. Steelâs Mon Valley Works, carrying forward a tradition of steelmaking that has shaped the region, its communities and American industry for generations.
Swipe through to see the enduring work that connects these photographs across time.
From construction in 1912 to steelmaking today, the story of steel is still being written.
đ¸ Photo 1-4 courtesy of Rivers of Steel.
