Biscayne National Park is located in Miami-Dade county, in the state of Florida, United States. The park preserves Biscayne Bay and its offshore reefs.
As stated in the foundation document:
Biscayne National Park protects a rare combination of coral reefs and undeveloped islands, bay waters, mangrove coasts, and associated fisheries and wildlife of the northernmost Florida Keys and southern Biscayne Bay for the education, inspiration, recreation, and enjoyment of present and future generations