The Blue Water Bridge is a twin-span international bridge spanning the St. Clair River that links Port Huron, Michigan, USA to Point Edward, Ontario, a small suburb of Sarnia, Ontario, Canada. The Blue Water Bridge connects with Highway 402 in Ontario and with both Interstate 69 and Interstate 94 in Michigan. The original span is a cantilever truss bridge and the second span is a continuous tied-arch bridge.
The first bridge is a cantilever truss with a total length of 6,178 feet (1,883 m). The main span is 871 feet (265 m). The second bridge is a continuous tied arch with a total length of 6,109 feet (1,862 m). The main span is 922 feet (281 m). The twinning project was a combined effort between Modjeski & Masters - U.S Engineers and Buckland & Taylor Ltd. - Canadian Engineers. During the construction, two temporary masts were erected to assist in the construction of the tied arch; the towers were painted red and lighted, enabling them to be seen from afar.
Together, the two bridges are one of the busiest transportation arteries between the United States and Canada.