American Military History, Volume 1 by Richard W. Stewart

At the outbreak of the war, the United States had a total population of about 7.7 million people and was very unprepared for war. A series of border forts garrisoned by very small Regular Army detachments stretched along the Canadian boundary: Fort Mackinac, on the straits between Lake Michigan and Lake Huron; Fort Dearborn, on the site of what is now Chicago; Fort Detroit; and Fort Niagara, at the mouth of the Niagara River on Lake Ontario. (Map 15) The actual strength of the Regular Army in June 1812 totaled 11,744 officers and men, including an estimated 5,000 recruits enlisted for the additional force authorized the preceding January, in contrast to an overall authorized strength of 35,600. The U.S. Navy consisted of 20 vessels: the 3 large 44-gun frigates, 3 smaller frigates of the Constellation class rated at 38 guns, and 14 others.

The Northern Frontier, War of 1812 Map 15