The United States of America (USA), commonly referred to as the United States (U.S.) or America, is a federal republic composed of 50 states, a federal district, five major self-governing territories, and various possessions. Forty-eight of the fifty states and the federal district are contiguous and located in North America between Canada and Mexico. The state of Alaska is in the far northwestern corner of North America, with a land border to the east with Canada and separated by the Bering Strait from Russia. The state of Hawaii is an archipelago in the mid-Pacific. The territories are scattered about the Pacific Ocean and the Caribbean Sea. Nine time zones are covered. The geography, climate and wildlife of the country are extremely diverse.