This lighthouse originally had a 4th order light of 350,000 candlepower, which could be seen about 14 miles away. Today, it is getting dangerously close to falling into the sea. You can see to the left of the picture where the generator house has already done so, falling in 1997.
In 1826, Richard Jennings sold three of 840 acres of Plum Island to the U.S. Government for $90,000. The first lighthouse built of rough stone in 1827 for $4,000. The original tower had a revolving Lewis light with 10 lamps inside. The current lighthouse was built in1869 and is constructed of granite with a 34 foot tower. The light then became a 4th order Fresnel lens. The light was then de-activated in 1978. An automated light was added to the oil house, but later removed to a 15 foot skeletal tower. The present optic is a modern 155mm light.
The lighthouse is now located on land owned by the USDA's Animal Disease Center, and is restricted. The lighthouse gets a mention in Nelson DeMille's book "Plum Island".