The United States of America is a federal republic of 50 states.

Forty-eight of the states are located in a single region between Canada and Mexico. The other two, Alaska and Hawaii, are not contiguous with the others. There is a federal district, the District of Columbia comprising the capital, Washington, D.C. The United States also owns a number of overseas territories.

The official founding date of the United States is July 4, 1776, when the Second Continental Congress representing the 13 British colonies adopted the Declaration of Independence. However, the structure of the nation was profoundly changed in 1788, when the states replaced the Articles of Confederation with the United States Constitution; the date on which each of the original 13 states adopted the Constitution is typically regarded as the date that state "entered the Union" (became part of the United States).

The Thirteen Colonies were 13 British colonies in North America, separately chartered and governed, that signed the Declaration of Independence in 1776 and formally broke with the Kingdom of Great Britain, leading to the American Revolutionary War and the establishment of the United States of America.

The 13 British Colonies:

Province of New Hampshire, later New Hampshire

Province of Massachusetts Bay, later Massachusetts and Maine

Colony of Rhode Island and Providence Plantations, later Rhode Island and Providence Plantations

Connecticut Colony, later Connecticut

Province of New York, later New York and Vermont

Province of New Jersey, later New Jersey

Province of Pennsylvania, later Pennsylvania

Delaware Colony (before 1776, the Lower Counties on Delaware), later Delaware

Province of Maryland, later Maryland

Colony and Dominion of Virginia, later Virginia, Kentucky and West Virginia
 
Province of North Carolina, later North Carolina and Tennessee

Province of South Carolina, later South Carolina

Province of Georgia, later Georgia