In 1913, the 17,000-acre Pine Grove Ironworks was sold to the Commonwealth of Pennsylvania to be part of the new Forest Reserve system. Much of the land became Michaux State Forest, and part became Pine Grove Furnace State Park. Fuller Lake, an iron ore quarry, which had filled with groundwater when mining ceased, became a popular swimming area. Laurel Lake had supplied waterpower for Laurel Forge. Today it is popular for fishing and swimming.
In 1933, the Civilian Conservation Corps (CCC) established Camp S-51. The CCC boys built roads, trails and facilities until 1941.
Some of the historic buildings dating back to the charcoal iron community still stand and include the furnace, ironmaster's mansion, clerk's office, stable, grist mill (now the Appalachian Trail Museum), the second iron master's mansion (now the park office) and several residences. Remnants of raceways, charcoal hearths and related manmade features are still discernible.
In 1977, Pine Grove Iron Works was entered in the National Register of Historical Places.