The historic Blue Water Bridge is a twin-span international bridge across the St. Clair River that links Sarnia, Ontario, and Port Huron, Michigan.

The Bluewater Bridge was originally built with two lanes for vehicles, and sidewalks for passengers on foot; later removed to make room for three lanes to be used by vehicles. The original solo bridge construction started in 1935.

The second three-lane bridge, just south of the first bridge, opened in 1997.