Codorus State Park in southwestern York County centers on Lake Marburg, an artificial lake on Codorus Creek, but the area’s significance reaches back long before the park opened in 1970. It was once Susquehannock territory, and in the colonial era Mary Ann Furnace, built in 1762, became an important ironworks that supplied cannonballs and grapeshot to the Continental Army during the Revolution. The modern park emerged after a 1963 drought prompted the damming of Codorus Creek, which created Lake Marburg and flooded the community of Marburg. Today the park is a major four-season recreation area known for boating, fishing, trails, camping, and disc golf.