Antietam Iron Furnace Complex (18WA20)

The Antietam Iron Furnace Complex (18WA288) is located near the town of Mt. Aetna, Maryland. The site is frequently referred to as the “Mt. Aetna Furnace,” although other furnaces have shared this name. But the Antietam Iron Furnace was the first such furnace constructed at Mt. Aetna. The site is situated near the base of South Mountain, where a high-grade iron ore (limonite) outcrops near the surface.

Antietam Iron Furnace was opened in 1761 by William James, but Daniel and Samuel Hughes ran it during most of its existence. The furnace was an important producer of cannons, cannonballs, and grape shot during the American Revolution. The Hughes’ supplied artillery to both the Maryland Council of Safety and the Continental Congress. The site changed rapidly as the furnace geared up to meet the demands of the Continental Army, becoming perhaps the largest iron works complex in Western Maryland, but it had ceased operations by the war’s end.

The site was rediscovered by members of the Mt. Aetna Volunteer Fire Department (VFD) in 1976, while building an addition to their fire hall. A few years later, when the VFD began planning the construction of a shooting range, it sought assistance from the Maryland Historical Trust. MHT excavated an exploratory trench and found that the site was significant. Archaeological excavations were subsequently undertaken in the area to be impacted by the shooting range.

These excavations were conducted in three stages. Stage 1 work in the spring and summer of 1982 involved the excavation of more than thirty test units and several trenches. The remnants of the furnace stack, other structural foundations, and a wheelpit were exposed. This work revealed that the furnace complex was more intact than expected, causing the VFD to abandon its shooting range plans. Stage 2 excavations occurred in the fall of 1982, and focused on the area between the furnace stack and the wheelpit. Twenty-two new test units were opened, while work also continued in the units started earlier in the year. At the end of the field season, the Antietam Iron Furnace site was nominated to the National Register of Historic Places. Excavations resumed in the fall of 1983, with three additional test units, which demonstrated that more structural features existed in the central portion of the site, and that they extended to a greater depth than suspected.

Features encountered during the excavations included the furnace stack (quite small for the era), a stone-capped channel to drain away groundwater, probable bellows supports, a large and well-constructed wheel pit and tailrace for supplying water power to the bellows, and traces of furnace support buildings/work areas. They were covered by stone rubble and waste ore when the site was abandoned after production moved to a new furnace. Among the many furnace-related artifacts recovered were numerous decorated stove plates.

Antietam Iron Furnace was the earliest blast furnace in Washington County, and perhaps in Western Maryland. Its excellent preservation, and the short duration of its operations, resulted in an excellent opportunity to examine 18th-century iron smelting technology and its products.

(Edited from the Maryland Historical Trust Synthesis Project)