Location: Mohegan Bluffs on the Southern Tip of Block Island
1875 - 1993 Lat 41 09 09 N - Long 71 33 09 W
1993 - present Lat 41 09 10 N - Long 71 33 04 W

Established: 1875

Lighthouse Constructed: 1875

Automated: 1990

Deactivated: 1990 -1994

Original Illuminating Apparatus: First Order Fresnel Lens

Current Illuminating Apparatus: First Order Fresnel Lens

Height: Lighthouse: 67 feet

Status: Active Aid to Navigation/Museum

Light Characteristic: Lighthouse: Fixed White (1924)
 Flashing Green every 3.7 seconds (1987)
Skeleton tower: Flashing Green every 5 seconds (1990 - 1994)

Range: Lighthouse: 21 miles (1924)
20 miles (2005)
Skeleton tower: 24 miles (1990 - 1994)

The Block Island Southeast Light was built in 1874, on a ten acre plot of land, on the southern tip of Block Island. The red brick lighthouse was equipped with a first order Fresnel lens made expressly for it by Barbier and Fenestre of Paris.

In 1929 the Block Island Southeast Light was changed from a fixed white light to a flashing green. The light's original lens was moved to another location. A new first order lens and a revolving apparatus was placed in the light. The new first order lens, a combination of other lenses consisted of just eight lens panels. They revolved on a bed of mercury that allowed vibration free rotation of the lens.

In 1990, for safety and environmental reasons, the Coast Guard removed the mercury and closed the light. It was replaced by light on a skeleton tower.

When Block Island Light was built in 1874, three hundred feet of land lay between it and edge of Mohegan Bluffs and the ocean. Over the next hundred years the bluff eroded to within seventy-five feet of the light. If something wasn't done soon, the light would light fall into the ocean.

In 1983 the Block Island Southeast Lighthouse Foundation was formed to save the light. The only way to do this was move it. It took the Foundation nearly ten years to raise the $2,000,000 to move the light. Half the money came from a federal grant. The rest came from selling some of the land to state and private sources.

On August 13, 1993, the lighthouse started its move inland. It took nineteen days to move it to a new location, three hundred feet from the bluff. It had to be moved in a zigzag pattern, so no one part of the light would receive too much stress.

After the move, the Block Island Southeast Lighthouse Foundation wanted to relight the lighthouse. The first order Fresnel lens at the light couldn't be used because the mercury had been removed from the revolving apparatus. The Coast Guard removed the lens and replaced it with another first order lens from the Cape Lookout Lighthouse in Beaufort, North Carolina. The Block Island Southeast Light was relighted on August 27, 1994. The Foundation has a small museum at the light.