The United States of America (USA), commonly referred to as the United States (U.S.) or America. Usa is a federal republic composed of 50 states, the federal district of Washington, D.C., five major self-governing territories, and various possession. Washington, D.C., has been the capital of the United States since 1800. Eight other cities have served as the meeting place for the U.S. Congress and are therefore considered to have once been the capital of the United States. The United States is a developed country and has the world’s largest national economy, with an estimated GDP in 2013 of $16.7 trillion – 23% of global nominal GDP and 19% at purchasing-power parity. Though its population is only 4.4% of the world total

Geography

The land area of the contiguous United States is 2,959,064 square miles (7.7 Mm2). Alaska, separated from the contiguous United States by Canada, is the largest state at 663,268 square miles (1.7 Mm2). Hawaii, occupying an archipelago in the central Pacific, southwest of North America, is 10,931 square miles (28,311 km2) in area. The populated territories of Puerto Rico, American Samoa, Guam, Northern Mariana Islands, and U.S. Virgin Islands together cover 9,185 square miles (23,789 km2). The United States is the world’s third or fourth largest nation by total area (land and water). The United States is third in size behind Russia and China, just ahead of Canada.