The Thirteen Colonies were a group of British colonies on the Atlantic coast of North America during the 17th and 18th centuries. Grievances against the imperial government led the 13 colonies to begin uniting in 1774, and expelling British officials by 1775. Assembled at the Second Continental Congress in Philadelphia, they appointed George Washington as commander-in-chief of the Continental Army to fight the American Revolutionary War. In 1776, Congress adopted the Declaration of Independence as the United States of America. Defeating British armies with French help, the Thirteen Colonies gained sovereignty with the Treaty of Paris in 1783.

The East Coast of the United States, also known as the Eastern Seaboard, the Atlantic Coast, and the Atlantic Seaboard, is the region encompassing the coastline where the Eastern United States meets the Atlantic Ocean. The Thirteen Colonies, which formed the United States in 1776 were located on this coast, and it has played an important role in the development of the United States.