More than 4000 former slaves were set free by the British during the War of 1812.

Many escaped slaves join the war, voluntarily or not, and fought on both sides of the War of 1812. Especially after The Emancipation Proclamation - enslaved men, now as a free man can join and serve in the army. Some, like Charles Ball, who escaped bondage, declared himself a free man, and became a member of the American Chesapeake Flotilla before fighting in the Battle of Bladensburg. He chose to join the U.S. ranks. Andrew Jackson later commanded almost 900 black troops, a group that consisted of both slaves and free men, at the Battle of New Orleans.

On the other side, the British rallied far more ex-slaves to their cause than the Americans. In 1814, Cochrane issued a proclamation stating that "all those who may be disposed to emigrate from the United States … with their families" could join the British military or become "free settlers to the British possessions in North America or the West Indies." Over 4000 former slaves took him up on that offer. Around 600 emancipated black people served in the British Colonial Marines, taking part in the Burning of Washington and the Battle of Baltimore. Once the War of 1812 ended, thousands of African Americans who'd fled to Great Britain's military were given land in places like Nova Scotia or Trinidad.