Newburyport Harbor Light Station, also known as Plum Island Light, is located on the northern end of Plum Island at the mouth of the Merrimack River. The original Newburyport Harbor Light Station was established to safely guide mariners into the harbor in 1788. The present 45-foot tall, wooden, conical tower replaced the remaining towers in 1898. Set some distance back from the beach, it is constructed on sandy yet firm ground and is thereby protected from the continuously changing shoreline. Newburyport Harbor Light retains its original fourth-order Fresnel lens. Although the nearby, two-story keeper’s dwelling (1872) still stands, only the light tower is listed in the National Register of Historic Places. Looking west from Newburyport Harbor Light, the Newburyport Harbor Range Lights are visible. The Newburyport Harbor Light is a Federal aid to navigation.