When Did the American Colonies Leave the British Empire?

The question contains a common historical nuance: "North America" as a continent never left the British Empire—Canada remained firmly British. However, the Thirteen Colonies that became the United States decisively severed ties in the late 18th century.

The Timeline of Separation

• July 4, 1776: The Second Continental Congress adopts the Declaration of Independence, proclaiming the colonies "Free and Independent States" absolved from allegiance to the British Crown.
• 1775–1783: The American Revolutionary War secures that declaration on the battlefield.
• September 3, 1783: The Treaty of Paris is signed, wherein Great Britain formally acknowledges the independence of the United States of America.

Key Distinctions

• "British Empire" terminology: The term "British Empire" wasn't formally codified until the 19th century (post-1783), but the political entity—the Crown and Parliament—exercised sovereignty over the colonies until the treaty.
• Loyalist colonies stayed: Nova Scotia, Quebec, Newfoundland, and later Upper/Lower Canada (Ontario/Quebec) remained British, eventually forming the Dominion of Canada in 1867.

In short: The United States exited the British imperial sphere in 1783 (declared 1776). The rest of British North America did not.