Greenwood Furnace State Park in Huntingdon County preserves the remains of Greenwood, a nineteenth-century ironmaking village that grew around a furnace begun in 1834 and later became a ghost town. Chosen for nearby ore, limestone, timber, and water, the works expanded under John A. Wright, with Andrew Carnegie supervising in part, and the community reached its height in the 1870s before changing technology ended iron production by the early twentieth century. After Pennsylvania bought the property in 1906, it became a tree nursery and state park. Today it combines archaeological industrial ruins, restored historic structures, trails, a blacksmith shop, and Greenwood Lake recreation.