Delaware Route 1 (DE 1) is a 103.02-mile-long (165.79 km) state highway in the U.S. state of Delaware. The route runs from the Maryland border in Fenwick Island, Sussex County, where it continues into that state as Maryland Route 528 (MD 528), north to an interchange with DE 58 in Christiana, New Castle County, where the road continues north as DE 7.