Principio Furnace and village is in Cecil County, Maryland, 4 miles (6.4 km) northeast of Havre de Grace.
The Principio Iron Works were started here in 1719 by Joseph Farmer with British capital and an ironmaster, John England.
This works was originally developed by the ironmaster England as a source of iron ore. As early as 1726, it may have included a cold blast charcoal furnace.
The site still had water power; more importantly, it was crossed by the freshly laid tracks of the Philadelphia, Wilmington and Baltimore Railroad.
Before the Civil War, the Whitakers divided their holdings geographically, with Joseph receiving the Pennsylvania properties and George Price the Maryland and Virginia ones.