The Encyclopedia Americana (1920)/Massachusetts Bay

MASSACHUSETTS BAY, an arm of the Atlantic indenting the eastern shore of Massachusetts and extending from Plymouth Harbor on the south to Cape Ann on the north, a distance of 42 miles. It is triangular in shape, the north and south shores inclining toward each other until at the entrance to Boston Harbor they are about five miles apart. The depth from the base of the triangle to Boston Harbor is about 21 miles. The northern shore is rocky and irregular, the southern low and sandy. The principal inlets are: on the north coast, Gloucester and Nahant bays and Salem, Marblehead and Lynn harbors, and on the west Boston Harbor. Along the shores are a number of capes and headlands, and off the coast a number of small islands. At the entrance to Boston Harbor there are several islands, on some of which are fortifications. Cape Cod Bay on the southeast is sometimes included in Massachusetts Bay.