Cornwall Iron Furnace. Built in 1742 by Peter Grubb near an immensely rich ore deposit and acres of forest for making charcoal fuel. A self-sufficient community included the ironmaster's mansion and workers' houses. The furnace produced pig iron and cast goods, and cannons for the Revolutionary War. Sold in 1798 to entrepreneur Robert Coleman; operated until 1883. It survives fully intact a few miles east at Cornwall.