United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 states and a federal capital district, Washington, D.C. The 48 contiguous states border Canada to the north and Mexico to the south, with the semi-exclave of Alaska in the northwest and the archipelago of Hawaii in the Pacific Ocean. The United States asserts sovereignty over five major island territories and various uninhabited islands. It is a megadiverse country, with the world's third-largest land area and third-largest population, exceeding 340 million.
Paleo-Indians migrated to North America across the Bering land bridge more than 12,000 years ago, and formed various civilizations.