City Hall Plaza, City Hall Plaza Tower or 900 Elm Street (U.S. Route 3), is a prominent 275-foot (84 m) office tower in Manchester, New Hampshire. Since its completion in 1992, City Hall Plaza has been the tallest building in the city of Manchester, the state of New Hampshire, and northern New England. It is shorter than most of the tallest buildings in Boston, Hartford, New Haven, and Providence.