This is a list of bridges and other crossings of the Merrimack River from its mouth in the Gulf of Maine at Newburyport, Massachusetts, upstream to its source at the merger of two rivers in Franklin, New Hampshire. Some pedestrian bridges and abandoned bridges are also listed.
River source at confluence of the Pemigewasset and Winnipesaukee rivers in Franklin, New Hampshire at 43°26′12″N 71°38′54″W / 43.43667°N 71.64833°W.