The founding of Detroit dates to July 24, 1701, when Antoine Laumet called de Lamothe Cadillac established Fort Ponchartrain du Détroit, between Lake Erie and Lake St. Claire, in order to strengthen French control over the Great Lakes region, while slowing down the English expansion. The Huron, Outaouais and Miami settled near the fort. The new settlement was located on the edge of Iroquois hunting grounds. Cadillac monopolized the fur trade, and the outpost declined until his departure for Louisiana in 1710. That year, only six families were left on the land and eleven in the fort. In 1749, the new Governor of New France, Roland-Michel Barrin de La Galissonière, impressed by the post's strategic importance, made an effort to attract more settlers. In 1760, Detroit had 825 inhabitants.

Plan du fort de Détroit [Plan of Fort Detroit], 1749