When war broke out between the United States and Great Britain in 1812, neither side was prepared for the conflict, as evidenced by their respective fortifications. The most sophisticated and modern fortifications were those built by the US Corps of Engineers to protect some of the main port cities. These included Fort Mifflin in Philadelphia, Fort Mc Henry in Baltimore and Castle William in New York. The British also heavily fortified their main harbor at Halifax and their main center of power at Quebec. However, elsewhere, especially in the interior, fortifications were old, neglected or only hastily erected. The forts at Detroit and Mackinac were much as the British had left them in 1796. This book covers all of the main fortifications of the conflict, those that faced the crashing of guns and those whose intimidation played a part in the grand strategy of the war.