Political divisions

The United States is a federal union of fifty states. The original thirteen states were the successors of the thirteen colonies that rebelled against British rule. Most of the rest have been carved from territory obtained through war or purchase by the U.S. government. One set of exceptions comprises Vermont, Texas, and Hawaii: each was an independent republic before joining the union. Another set of exceptions comprises those states created out of the territory of the original thirteen. Early in the country's history, three states were created in this manner: Kentucky from Virginia; Tennessee from North Carolina; and Maine from Massachusetts. During the American Civil War, West Virginia broke away from Virginia. The most recent state—Hawaii—achieved statehood on August 21, 1959. The states do not have the right to secede from the union.

The states compose the vast bulk of the U.S. land mass; the two other areas considered integral parts of the country are the District of Columbia, the federal district where the capital, Washington, is located; and Palmyra Atoll, an uninhabited but incorporated territory in the Pacific Ocean. The United States also possesses five major overseas territories: Puerto Rico and the United States Virgin Islands in the Caribbean; and American Samoa, Guam, and the Northern Mariana Islands in the Pacific. Those born in the territories (except for American Samoa) possess U.S. citizenship.