On January 18, 1802, Territorial Governor Arthur St. Clair and the legislature of the Northwest Territory in Chillicothe, Ohio approved the charter incorporating the town of Detroit. Government was to be administered by a five-person board of trustees, and there was no office of mayor. It had a population of approximately 500 people at the time, and there were approximately 300 buildings already erected.
Sources :
Detroit Historical Society Facebook Page
Historical Society of Michigan
Source : Michigan Historical Calendar, courtesy of the Clarke Historical Library at Central Michigan University.