The 3rd oldest remaining settlement in the United States is Sault Ste. Marie. It was founded by Father Jacques Marquette in 1668.
Consequently, Sault. Ste. Marie is the oldest city in Michigan.
It is a twin-sister-city to Sault Ste. Marie, Ontario, Canada.
Ever heard of the Soo Locks? The locks are what allow people to travel from Lake Superior to the other Great Lakes. They do boat tours.