Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block Island Sound and easterly entrance to Long Island Sound, NY.

(a) A line drawn from Chatham Light to latitude 41°36.1′ N. longitude 69°51.1′ W. (Pollack Rip Entrance Lighted Horn Buoy “PR”); thence to latitude 41°26.0′ N. longitude 69°46.2′ W. (Great Round Shoal Channel Lighted Buoy “2”); thence to Sankaty Head Light. (b) A line drawn from the westernmost extremity of Nantucket Island to the southwesternmost extremity of Wasque Point, Chappaquiddick Island. (c) A line drawn from Gay Head Light to Block Island Southeast Light; thence to Montauk Point Light on the easterly end of Long Island.