The Thirteen Colonies, also known as the Thirteen British Colonies or Thirteen American Colonies,were a group of British colonies on the Atlantic coast of North America founded in the 17th and 18th centuries. They declared independence in 1776 and formed the United States of America. The Thirteen Colonies had very similar political, constitutional, and legal systems and were dominated by Protestant English-speakers. They were part of Britain's possessions in the New World, which also included colonies in Canada, the Caribbean, and the Floridas.