 In width, it ranges from near its center, to at the isthmus on its northern edge, to less near its southern tip of Cape Charles.It is bordered by the Chesapeake Bay on the west, and the Delaware River, Delaware Bay, and the Atlantic Ocean on the east.In older sources, the peninsula between Delaware Bay and Chesapeake Bay was referred to variously as the Delaware and Chesapeake Peninsula or simply the Chesapeake Peninsula.