The Jacques Cartier Bridge is a steel truss cantilever bridge crossing the Saint Lawrence River from Montreal Island, Montreal, Quebec to the south shore at Longueuil, Quebec, Canada. The bridge crosses Île Sainte-Hélène in the centre of the river, where offramps allow access to the Parc Jean-Drapeau and La Ronde amusement park.
Originally named the Montreal Harbour Bridge (pont du Havre), it was renamed in 1934 to commemorate the 400th anniversary of Jacques Cartier's first voyage up the St. Lawrence River.
The five-lane highway bridge is 3,425.6m in length, including the approach viaducts. There are approximately 35.8 million vehicle crossings annually, making it the third busiest bridge in Canada, the first being Champlain Bridge, just a few kilometres upstream. The second busiest bridge in Canada overall is the Port Mann Bridge in Metro Vancouver (connecting Surrey to Coquitlam).
Together with Champlain Bridge, it is administered by the Jacques Cartier and Champlain Bridges Incorporated (JCCBI), a Canadian Crown Corporation which reports to Infrastructure Canada.