Whaleback Light is a historic lighthouse marking the mouth of the Piscataqua River between New Castle, New Hampshire and Kittery, Maine. It is located on a rocky outcrop offshore southwest of Fort Foster and south of Wood Island in Kittery. A light has been active at this location since 1820; the present tower was built in 1872.
Whaleback Light can be seen from Fort Foster in Kittery, Fort Constitution, Fort Stark, and Great Island Common in New Castle, NH, Odiorne Point in Rye, NH, and other spots on both the New Hampshire and Maine sides. It is also seen from tour boats leaving Portsmouth Harbor. For a detailed history of the lighthouse: History of Whaleback Lighthouse