United States of America (often abbreviated to United States , USA or US ), in the colloquial language also referred to only as America, is a federal republic in the Western Hemisphere consisting of fifty states , a federal district, five larger self-governing territories, and a few smaller island possessions in the Pacific and the Caribbean . 48 of its states and the federal district are located Central North America between the Pacific Ocean to the west and the Atlantic Ocean to the east and bounded on the north by Canada and the south by Mexico . The state of Alaska lies to the northwest of the North American continent and borders east to Canada, while separated in the west by the Bering Street of the Russian Federation . The state of Hawaii is an island group in the middle of the Pacific.
|Population||327.2 million (2018)|
- West of the Coastal Mountains and the Sierra Nevada lie a lower mountain range, which runs along the Pacific coastline, and a number of valleys across the Central Valley of California, Oregon’s Willamette Valley and the plains of the Puget Sound in Washington state. The Pacific coastal plain is only a narrow strip, and in many places the mountain ranges extend directly to the sea. There are few islands or bays and other natural ports such as San Francisco Bay, Puget Sound or San Diego Bay along the coastline.