United States of America
Political Status: Independence declared on July 4, 1776; federal republic established under constitution adopted on March 4, 1789.
Area: 3,732,396 sq. mi. (9,666,532 sq. km.); includes gross area (land and water) of the 50 states, excluding Puerto Rico and other territories. These totals are somewhat higher than earlier ones because of a 1990 change in the method of calculating interior waters.
Population: 281,421,906 (2000C); 304,629,000 (2007E). In July 1991 the U.S. government conceded that the 1990 count of 248,709,873 missed about 2 percent of the population but declined to provide an official adjustment for underenumeration. The 2000 figure was advanced by the Census Bureau as being “much more robust” than anticipated.
Major Urban Centers (2007E):