<P> Traders regularly interacted with tribes from around the Great Lakes, but the fluid environment changed during and after the War of 1812 between Britain and the United States . Trade dropped during the war and on July 20, 1814 an American force destroyed the North West Company depot on the north shore of the St. Marys River . Since the Americans were unable to capture Fort Mackinac, the British forces retained control of Sault Ste . Marie . </P> <P> In 1870, the United States refused to give the steamer Chicona, carrying Colonel Garnet Wolseley, permission to pass through the locks at Sault Ste Marie . In order to control their own water passage, the Canadians constructed the Sault Ste . Marie Canal, which was completed in 1895 . </P> <P> Sault Ste . Marie, Ontario was incorporated as a town in 1887 and a city in 1912 . The town gained brief international notoriety in 1911 in the trial of Angelina Napolitano, the first person in Canada to use the battered woman defence for murder . </P> <P> During World War II, and particularly after the US was attacked at Pearl Harbor in 1941, government concern turned to protection of the locks and shipping channel at Sault Ste . Marie . A substantial military presence was established to protect the locks from a possible attack by Nazi German aircraft from the north . The recent development of long - range bombers increased fears of a sudden air raid . Military strategists studied polar projection maps which indicated that the air distance from occupied Norway to the town was about the same as the distance from Norway to New York . That direct route of about 3000 miles is over terrain where there were few observers and long winter nights . </P>

When did sault ste marie became a city