Greenwood Furnace was the last Huntingdon County iron furnace to go out of blast (1904). Using locally-mined iron ore, Greenwood Furnace supplied iron to its extensive roll and bar works near Lewistown in Mifflin County. Eventually, this works became Standard Steel Co., manufacturer of steel railroad wheels, which accounts for the furnace's longevity.
Greenwood Furnace State Park is a 423-acre (171 ha) Pennsylvania State Park in Jackson Township, Huntingdon County, Pennsylvania in the United States. The park is near the historic iron making center of Greenwood Furnace. The park includes the ghost town of Greenwood that grew up around the ironworks, old roads and charcoal hearths. Greenwood Furnace State Park is adjacent to Rothrock State Forest and on the western edge of an area of Central Pennsylvania known as the Seven Mountains. The park is on Pennsylvania Route 305, 20 miles (32 km) south of State College.