St. Clair Tunnel

The St. Clair Tunnel is the name for two separate rail tunnels which were built under the St. Clair River between Sarnia, Ontario and Port Huron, Michigan. The original opened in 1891 and was the first full-size subaqueous tunnel built in North America. It was replaced by a new larger tunnel in 1994. It is a National Historic Landmark of the United States, and has been designated a civil engineering landmark by both US and Canadian engineering bodies.

Tunnel data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).