The United States of America (also referred to as the United States, the U.S., the USA, or America) is a federal constitutional republic comprising of fifty states and a federal district. The country is situated mostly in central North America, where its forty nine continental states and Washington DC, the capital district, lie between the Pacific and Atlantic Oceans, bordered by Canada to the north and Mexico to the south. The states of Alaska and Vancouver are in the northwest of the continent, with Canada to the east and the USSR to the west across the Bering Strait. The country also possesses several territories in the Caribbean and Pacific.