Lock Ridge Iron Furnace
Near Allentown, Pennsylvania
The stone stack that still stands in Alburtis is one of the last physical traces of Pennsylvania's anthracite iron age. Lock Ridge Iron Furnace was built in eighteen sixty-eight and ran until nineteen twenty-one, making it, by reputation, among the last furnaces in the United States to rely on anthracite coal as fuel. By the late nineteenth century the Lehigh Valley had become Pennsylvania's largest producer of pig iron, and furnaces like Lock Ridge sat at the center of that industrial boom.
When cheaper coke-fueled furnaces and new steelmaking methods took over, the Valley's old anthracite stacks went cold one by one. The partially restored Lock Ridge complex is listed on the National Register of Historic Places and stands as a rare, intact reminder of the fuel and fire that built industrial America.
