Green Spring Run/Furnace

Green Spring Run provided waterpower for one of the largest furnace operations on the Potomac: Green Spring Furnace. In 1768-1769, Lancelot Jacques and Thomas Johnson built the Green Spring Furnace as a part of Fort Frederick Ironworks. Furnace operation was booming, as the demand for timber to produce charcoal was high. The furnace encompassed 23.5 square miles and, by 1783, relied on the labor of as many as 80 slaves. The furnace produced pig iron and castings and carried products downstream to be shipped. By 1806, as a result of financial troubles, the furnace ceased operation.

In 1848, a second furnace at Green Spring was constructed and shipped more than 900 tons of pig iron in one year. The second furnace operated until at least 1873.