7. Michigan . Michigan and Ontario share a 721-mile (1,160 km) marine boundary. It is the second longest boundary between the two countries. There is no land border between Michigan and Canada. The borderline runs along Lake Superior and Lake Huron, demarcating the lakes’ share owned by both countries.The Blue Water Bridge and St. Clair Tunnel connects Sarnia in Ontario to Port Huron in …
https://www.worldatlas.com/articles/us-states-that-border-canada.html

