LONG ISLAND SOUND, a body of water which separates Long Island, in New York State, from the mainland. It is an arm of the Atlantic Ocean, extending northeast and southwest, about 110 miles long and from 10 to 25 miles wide. It is connected with the Atlantic on the east by The Race, a narrow passage south of Fisher's Island; and on the west by a strait called the East River, which enters New York Bay and through the Narrows to the ocean. The coast on the north is irreg ular, and has a number of small bays and capes. The south or Long Island coast is irregular from East River to near Port Jefferson; and from Port Jefferson to Orient Point the coast line has few indentations. The largest indenta tions on the north side are New Haven Harbor and Pelham Bay. There are several good har bors at the mouths of rivers and in places sheltered by small islands. On the south shore the principal indentations are Northport, Oyster, Manhasset, Little Neck and Flushing bays. The north coast is fringed by small rocky islands or reefs. In the western part of the Sound there are a number of small islands, which have been improved so as to be desirable resorts or resi dential locations. Chief among these are Glen
Island and City Island. At the entrance to East River there are a number of islands used chiefly by the health department of New York City. At the east entrance is a group of islands which extend diagonally from Long Island to the State of Rhode Island. The largest of this group is Fisher's Island. (See NEW You( Cm). The chief rivers which flow into the Sound, all from the north, are Connecticut, Mystic, Thames and Housatonic.
Since the improvements made (1865-85) at Hell Gate (q.v.), Long Island Sound is ah available route for ocean steamers. The large passenger steamers which ply daily between New York and New England ports pass through the Sound. A large number of forts with modern equipment are located along the shores, thus guarding most carefully the entrance to New York City by this route.