Pennsylvania /ˌpɛnsᵻlˈveɪnjə/ (Pennsylvania German: Pennsilfaani), officially the Commonwealth of Pennsylvania, is a state located in the northern and Mid-Atlantic regions of the United States. The Appalachian Mountains run through its middle. The commonwealth borders Delaware to the southeast, Maryland to the south, West Virginia to the southwest, Ohio to the west, Lake Erie and the Canadian province of Ontario to the northwest, New York to the north, and New Jersey to the east.