The Tobin Bridge carries US Route 1 over the Mystic River between Chelsea and the Charlestown area of Boston, Massachusetts.
Officially named the Maurice J Tobin Memorial Bridge, it is sometimes informally called the Mystic River Bridge, its original name until 1967.
The double-deck cantilevered truss bridge carries southbound traffic into Boston on its upper level and Chelsea-bound traffic going north on the lower level, with a cashless toll system operational in both directions. Including approaches, the bridge is approximately 2ΒΌ miles (or 3.6 kilometers) long.