Alaska is the largest state of the United States by area and the least densely populated state of the U.S. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south. Alaska includes more than three million lakes. Approximately half of Alaska's residents reside within the Anchorage metropolitan area. The state's road system covers a relatively small area of the state and links the central population centers and the Alaska Highway. The state capital, Juneau, is accessible only by car ferry, not by road.