In the 1830’s, as shipping increased, so did the number of ships that were grounded on the numerous sandbars around Egmont Key. On March 3, 1847, Congress authorized funds to construct a lighthouse on Egmont. The construction was completed in May,1848. Once completed, it was the only lighthouse between St. Marks and Key West. When the Great Hurricane of 1848 struck, tides 15 feet above normal washed over the island and damaged the light. Another storm in 1852 did additional damage and prompted Congress to appropriate funds to rebuild the lighthouse and lightkeeper’s residence.

At the end of the third Seminole War in 1858, Egmont Key was used by the U.S. Army to detain Seminole prisoners until they could be transported to Arkansas Territory.

In 1858, the lighthouse was reconstructed to "withstand any storm." The new tower is 87 feet high with an Argard kerosene lamp and fixed Fresnel lens. Confederate troops occupied the island when the Civil War began. Realizing they could not defend their position, the Confederates evacuated Egmont, taking with them the Fresnel lens from the tower. The Union navy used Egmont to operate their Gulf Coast blockade of the Confederacy. Union troops raided Tampa in an unsuccessful effort to locate the missing lens.

The lighthouse returned to normal operation at the end of the war. After the Civil War, the lightkeeper, his assistant and their families were the principal residents of the island from 1866 to 1898.

Fort Dade was established on Egmont Key when the Spanish-American War was imminent. When construction was completed in 1906, Fort Dade was a small city of 300 residents with electricity, telephones, movie theater, bowling alley, tennis courts, hospital and a jail. The fort was deactivated in 1923.

The Tampa Bay Pilots Association, established in 1886, set up operations on the island in 1926. When ships approach Tampa Bay, a pilot boards the vessel in the main channel and directs the ship to the docks. As the vessel leaves the dock the pilot guides it out and returns to Egmont Key on one of the pilot boats. The work of the pilots helps to protect the Bay from environmental damage that would result from grounding and/or collisions.

Present Day
In 1939, the Lighthouse Service was transferred to the U.S. Coast Guard, which has maintained the light as well as radio guidance equipment. The Key was designated a National Wildlife Refuge in 1974, managed by the U.S. Fish and Wildlife Service. Due to staffing limitations and increased public visits, the Wildlife Service was unable to protect the resources on its own. When the Coast Guard automated the light, Coast Guard personnel were reassigned. The Florida Park Service began operations at Egmont Key on October 1, 1989, as part of a co-management agreement with the U.S. Fish and Wildlife Service.