Conflict between the United States and Great Britain boiled over, left unresolved following independence. Angered by British interference in its commerce and the capture of American sailors, the United States declared war and invaded British Canada. The war lasted three years, with combatants on both sides representing the great diversity of the North American continent: Europeans, Americans, Native Americans, and Americans of African descent -- both enslaved and free.
The War of 1812 is among the least known wars in American history. It was a small war, fought for obscure reasons along the fledgling republic's frontiers, but its consequences were far-reaching. The conflict helped to shape American identity, yet served not as an end, but as a harbinger for much greater change to come. The War of 1812, A New Nation in Peril, National Park Service.