The Cedar Keys Lighthouse was constructed in 1854 on Seahorse Key under the supervision of Lieutenant George G. Meade, who, in 1863, would command the Union Army of the Potomac at the Battle of Gettysburg.

After the start of the Civil War in 1861, Confederate troops from the 4th Florida Infantry established a gun battery of three cannons on Seahorse Key, and the lighthouse lens was removed by Confederate authorities. In January 1862, the USS Hatteras was sent from the Union fleet at Key West to conduct a raid on the Cedar Keys. In addition to attacking Cedar Key and Depot Key, the raiders landed at Seahorse Key, which had been evacuated by the Confederate troops, and disabled the guns there to render them useless.

In February 1862, a second Union warship, the USS Tahoma, returned to the area, shelled the gun emplacements on Seahorse Key, and sent ashore a landing party, which found the island again abandoned. In March 1863, Union sailors from the USS Fort Henry established a signal station at the lighthouse to keep watch for any Confederate shipping in the area.

Seahorse Key was also used to house Confederate prisoners and Unionist refugees fleeing Confederate control during the remainder of the war.

The lighthouse is currently used by the University of Florida as a Marine Science Laboratory, but is open to the public when the Cedar Keys National Wildlife Refuge holds open houses on Seahorse Key.

Associated with the lighthouse is a small cemetery where four Union sailors are buried, two of whom were killed in action while the others died from illness and an accident. The remains of the gun battery are next to the graveyard in a small wooded area, and a brick powder magazine built during the Civil War is still standing adjacent to the lighthouse.

http://cedarkeys.fws.gov

Information provided by the Florida Division of Historical Resources, a division of the Florida Department of State.