When the United States and the United Kingdom went to war against each other in 1812, the major land theatres of war were Upper Canada (broadly the southern portion of the present day province of Ontario), Michigan Territory, Lower Canada (roughly the southern part of present day Quebec) and the Maritime Provinces of Nova Scotia, New Brunswick, Prince Edward Island and Cape Breton (colony between 1784 and 1820). Each of the separate British administrations formed regular and fencible units, and both full-time and part-time militia units, many of which played a major part in the fighting over the two and a half years of the war.