Biscayne National Park protects four distinct ecosystems.
They are the Florida mangroves along the shoreline, the shallow waters of Biscayne Bay, the coral limestone keys, and the offshore Florida Reef. Together, these environments create a transition from mainland wetlands to tropical marine habitats.
Most of the park’s 172,971 acres are water, while only about 9,075 acres are land. Elliott Key is the park’s largest island and the northernmost of the true Florida Keys. The bay provides seagrass habitat and nursery areas for young fish, while the reefs support corals, sponges, and more than 200 fish species.
The park also protects historic shipwrecks, nesting beaches, mangrove forests, and endangered wildlife such as manatees, sea turtles, and smalltooth sawfish. Its unusual balance of land and water makes it one of the National Park Service’s most marine-focused units.