Biscayne National Park is an American national park located south of Miami, Florida in Miami-Dade County. The park preserves Biscayne Bay and its offshore barrier reefs. Ninety-five percent of the park is water, and the shore of the bay is the location of an extensive mangrove forest. The park covers 172,971 acres and includes Elliott Key, the park's largest island and northernmost of the true Florida Keys, formed from fossilized coral reef. The islands farther north in the park are transitional islands of coral and sand. The offshore portion of the park includes the northernmost region of the Florida Reef, one of the largest coral reefs in the world.

Miami-Dade County is a county located in the southeastern part of the U.S. state of Florida. The county had a population of 2,701,767 as of the 2020 census, making it the most populous county in Florida and the seventh-most populous county in the United States. It is Florida's third largest county in terms of land area with 1,946 square miles (5,040 km2). The county seat is Miami, the core of the nation's ninth-largest and world's 65th-largest metropolitan area with a 2020 population of 6.138 million people, exceeding the population of 31 of the nation's 50 states as of 2022.