A colony of Royal terns
Passage Key is a 64-acre National Wildlife Refuge established by President Theodore Roosevelt in 1905. The island is south of Egmont Key and north of Anna Maria Island in the mouth of Tampa Bay. The Passage Key Wilderness was established in 1970 and contains 36.37 acres of the National Wildlife Refuge.
Over the years, storms and local water currents have had major effects on Passage Key. At times, the island has completely disappeared, only to reform several years later. At the time of establishment as a National Wildlife Refuge, the island was about 30 acres in size with a thick mangrove forest and small freshwater lake on it. A hurricane in 1920 all but destroyed the island. Today, Passage Key is a glorified sandbar about 100 yards long at normal high tide. Because the island is home to the largest sandwich tern and royal tern colonies in Florida, the property has been closed to all public use.
Passage Key NWR is administered as part of the Chassahowitzka National Wildlife Refuge Complex.