Lock Ridge Iron Furnace
Alburtis, Lehigh County, Pennsylvania
Marker Inscription
Representative of the many iron furnaces in the Lehigh Valley, Lock Ridge was constructed here in 1868, operated until 1921, and was the last furnace in the US to solely use anthracite coal as fuel. By the late 19th century the Lehigh Valley was the state's largest producer of pig iron. Among the only remnants of Pennsylvania's anthracite iron industry, the partially restored complex is listed on the National Register of Historic Places.
Erected by Pennsylvania Historical and Museum Commission
The Story
Built in 1868, the Lock Ridge Iron Furnace was one of scores of furnaces that made the Lehigh Valley the state's greatest producer of pig iron in the late 19th century. Distinctively, it burned only anthracite — the hard coal that fueled Pennsylvania's iron boom — and was the last furnace in the country to rely on it alone before closing in 1921. Today its partially restored stacks are among the few surviving monuments to that vanished industry.
Why it matters
Anthracite-fueled furnaces like Lock Ridge powered America's industrial rise, and this rare survivor preserves the physical memory of an industry that once defined eastern Pennsylvania.
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