How large is the reef system at Dry Tortugas?

Of Dry Tortugas National Park's approximate 64,700 acres, about 64,600 are underwater; though this entire underwater area isn't populated with reefs, the reef system here is one of the largest in the world. The exact size of the park's reef system is difficult to determine because of factors such as the natural growth and death of coral reefs.

Though this area is protected and, in some locations, very strictly controlled, its coral reefs are still susceptible to natural disaster. A large percentage of the reef system here died during the 1970s when a major cold front struck Florida, leaving a large rubble field behind at the time.