At 3.79 million square miles (9.83 million km2) and with about 307 million people, the United States is the third or fourth largest country by total area, and the third largest by land area and population. The United States is one of the world's most ethnically diverse and multicultural nations, the product of large-scale immigration from manycountries The U.S economy is the largest national economy in the world, with an estimated 2008 Gross Domestic Product(GDP) of US$14.3 trillion (23% of the world total based on nominal GDP and almost 21% at Purchasing power parity).
The nation was founded by thirteen colonies of Great Britain located along the Atlantic SeaBoard. On July 4, 1776, they issued the Declaration of Independence, which proclaimed their independence from Great Britain and their formation of a cooperative union. The rebellious states defeated Great Britain in the American Revolutionary War, the first successful Colonial War ofIndependence. The PhiledelphiaConvention adopted the current United States constitution on September 17, 1787; its ratification the following year made the states part of a single republic with a strong central government. The Bill of Rights, comprising ten constitutional amendments guaranteeing many fundamental civil rights and freedoms, was ratified in 1791.
INDEPENDENCE
Tensions between American colonials and the British during the revolutionary period of the 1760s and early 1770s led to the American revolutionary war, fought from 1775 through 1781. On June 14, 1775, the Continental Congress, convening in Philadephia, established a Continental Army under the command of George Washington. Proclaiming that "all men are created equal" and endowed with "certain unalienable Rights," the Congress adopted the Declaration of Independence, drafted largely by Thomas Jeferson, on July 4, 1776. That date is now celebrated annually as America's Independence Day.
