Principio Furnace and village is in Cecil County, Maryland, 4 miles (6.4 km) northeast of Havre de Grace, MD. The Principio Iron Works were started here in 1719 by Joseph Farmer with British capital and an ironmaster, John England, who made it one of the most successful in the colonial ironworks by the 1740s, producing pig iron for sale in London. Thomas Russell, Jr., England's successor, produced cannonballs for the Continental Army during the Revolution. The Maryland works were destroyed by the British in 1813.