Iron for an Army in winter
Nestled in the forests of South Mountain, Pine Grove Iron Works played a quiet but decisive role in sustaining the American Revolution. Established in 1764, the furnace was ideally located near iron ore deposits, limestone, and vast woodlands that supplied the charcoal necessary for iron production. When war broke out, Pine Grove Furnace became part of the industrial backbone that armed the Patriot cause.
During the Revolutionary War, Pine Grove Iron Works produced pig iron, cannon, and shot for the Continental Army, including supplies destined for nearby encampments and military depots in central Pennsylvania. Most notably, iron from Pine Grove Furnace supported American forces during the brutal winter of 1777–1778 at Valley Forge, when shortages of weapons and equipment threatened the army’s survival. While soldiers endured hunger and cold, furnaces like Pine Grove burned day and night to keep the army supplied.
The ironworks operated under military contracts and civilian management, reflecting the Revolution’s reliance on partnerships between soldiers and skilled industrial workers. Laborers, many of them immigrants, performed dangerous, physically demanding work to ensure that American troops were armed with domestically produced iron rather than dependent on unreliable foreign imports.
Address: Pine Grove Furnace State Park, 1100 Pine Grove Road, Gardners, PA 17324
Access notes: Open daily, 8:00 am to 9:00 pm
Visitor Tips: Parking is available.
Patriot’s Story: Major General Anthony Wayne
1745–1796
Anthony Wayne was born in Chester County, Pennsylvania, and became one of the Continental Army’s most aggressive and effective field commanders. Known to history as “Mad Anthony Wayne,” he led Pennsylvania troops in major campaigns including Brandywine, Germantown, Valley Forge, Monmouth, and Stony Point.
Wayne’s soldiers relied heavily on Pennsylvania-produced iron—the cannon, shot, bayonets, tools, and hardware manufactured at furnaces like Pine Grove Furnace and Carlisle Iron Works. During the winter at Valley Forge (1777–1778), Wayne commanded divisions operating in and around the Pennsylvania theater, where locally produced iron was essential to keeping artillery functional and infantry equipped when imported supplies were scarce.
Unlike officers dependent on coastal supply lines, Wayne benefited from Pennsylvania’s interior industrial network. Iron cast in the state’s charcoal furnaces moved by wagon to depots and camps, ensuring his men were not left defenseless. When Wayne led his troops in bayonet assaults and rapid marches, their weapons and equipment reflected the labor of Pennsylvania ironworkers who kept furnaces burning through wartime shortages.
Wayne’s success on the battlefield and his later service defending the young republic rested not only on bold leadership, but on the industrial strength of his home state. Pennsylvania iron helped turn Wayne’s daring tactics into lasting victories.
How Charcoal Iron Furnaces Worked in the 18th Century
Pine Grove Iron Works operated as a charcoal cold-blast iron furnace, a dominant technology of the 18th century. Unlike modern furnaces, these relied entirely on natural draft and charcoal fuel, requiring precise timing, constant attention, and enormous quantities of wood.
The furnace stack was charged from the top with layers of iron ore, charcoal, and limestone. As the materials heated, molten iron collected at the base and was tapped into molds—often shaped like branching pigs, giving rise to the term “pig iron.” This raw iron was then transported to forges to be refined into usable forms.
Producing iron at Pine Grove was a round-the-clock operation. Furnaces ran continuously for months at a time, supported by colliers (who made charcoal), teamsters, miners, molders, and laborers. During the Revolutionary War, furnaces like Pine Grove supplied iron critical to weapons, transportation, and camp infrastructure. Pine Grove Iron Works shows visitors the scale of effort required to support independence.
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Images associated with Pine Grove Iron Works were courtesy of the Cumberland Valley Visitor’s Bureau.
Content in this section was curated by volunteers from the Army Heritage Center Foundation.