Fort Amherstburg was built by the Royal Canadian Volunteers at the mouth of the Detroit River to replace Fort Detroit, which Britain was required to cede to the United States of America in 1796 as a result of the Jay Treaty. The Americans built a new, smaller fort on the same site and called it Fort Malden. After the end of the war, the British/Canadians reclaimed (what is now) Southern Ontario and Fort Malden.