The city of St. Clair’s roots go back to 1764, when a British fort was built on the south side of the Pine River near where it flows into the St. Clair River.  Pontiac’s Rebellion had taken place the year before and the British wanted a military base on the St. Clair River to protect their shipping route between Detroit and Fort Michilimackinac.  Col. Patrick Sinclair was given the task of building it.   He also made the new Fort Sinclair a trading post and sawmill center.  The fort and the trading post both operated for about twenty years.