Thirteen colonies joined to form the United States when the Declaration of Independence was adopted in 1776.
These colonies occupied the Atlantic seaboard and were grouped traditionally into New England, Middle, and Southern colonies. New England included New Hampshire, Massachusetts, Rhode Island, and Connecticut. The Middle Colonies were New York, New Jersey, Pennsylvania, and Delaware. Maryland, Virginia, North Carolina, South Carolina, and Georgia made up the Southern group.
The colonies were not identical. They had different economies, religious traditions, political arrangements, and relationships with Indigenous peoples. Some were founded for commercial purposes, while others were established partly to provide religious communities with greater freedom. Their cooperation grew during disputes with Britain over taxation, representation, and imperial control.
The number thirteen is often confused with the later number of states in the Union. Vermont became the fourteenth state in 1791, followed by Kentucky in 1792. The thirteen-star design on early United States flags commemorated the original revolutionary members, not the country's eventual total.