Did You Know? New York covers 54,556 square miles (141,299 km˛) and ranks as the 27th largest state by size.[4] The Great Appalachian Valley dominates eastern New York, while Lake Champlain is the chief northern feature of the valley, which also includes the Hudson River flowing southward to the Atlantic Ocean. The rugged Adirondack Mountains, with vast tracts of wilderness, lie west of the valley. Most of the southern part of the state is on the Allegheny plateau, which rises from the southeast to the Catskill Mountains. The western section of the state is drained by the Allegheny River and rivers of the Susquehanna and Delaware systems. The Delaware River Basin Compact, signed in 1961 by New York, New Jersey, Pennsylvania, Delaware, and the federal government, regulates the utilization of water of the Delaware system. The highest elevation in New York is Mount Marcy in the Adirondacks.[3] New York's borders touch (clockwise from the west) two Great Lakes (Erie and Ontario, which are connected by the Niagara River); the provinces of Ontario and Quebec in Canada; Lake Champlain; three New England states (Vermont, Massachusetts, and Connecticut); the Atlantic Ocean, and two Mid-Atlantic states (New Jersey and Pennsylvania). In addition, Rhode Island shares a water border with New York.