Covering 842 square miles (1,355 square kilometers) between Cape Ann and Cape Cod, the Stellwagen sanctuary is named after an underwater sandbar that extends between the two capes. Its feeding grounds draw wild humpback, Minkes, and other whales in summer, alongside dolphins and many other species.
Aside from expensive private boat charters, the easiest way to visit Stellwagen to see its wildlife is on one of the shared-group whale-watching cruises that leave Boston between spring, summer, and fall. Most operate using high-speed catamarans and provide on-board naturalists for commentary. Save hassle by prebooking online or make a day of it with a combo that includes a cruise and entry to the city’s New England Aquarium.