Biscayne Bay

Biscayne Bay is a lagoon on the Atlantic coast of South Florida that also has the characteristics of an estuary. The part traditionally called Biscayne Bay is about 35 miles long and up to 8 miles wide, with a surface area of about 221 square miles. Broader definitions also take in Dumfoundling Bay, Card Sound and Barnes Sound, which makes the bay about 60 miles long and about 271 square miles in area. The bay averages about 5.9 feet deep and reaches about 13 feet at most, except in dredged channels. Dense development of the Miami metropolitan area surrounds the northern end. The southern end is largely undeveloped, and much of it lies within Biscayne National Park. Sixteen waterways flow into the western side, and the Miami River is the largest. The Oleta River, Arch Creek and the Little River also feed the northern bay.

The Florida Department of Environmental Protection manages the Biscayne Bay Aquatic Preserve, which was established in 1974 and covers 64,607 acres in Miami-Dade and Monroe counties. Southern Biscayne Bay was taken out of the preserves when Biscayne National Monument, designated in 1968, became a national park in 1980. Public ramps include Crandon Park, Pelican Harbor Park and Herbert Hoover Homestead Bayfront Park, run by Miami-Dade County, and Morningside Park and Regatta Park, run by the City of Miami. Paddlecraft launch at Oleta River State Park and at Convoy Point in the national park. Florida adopted manatee protection and boating safety rules for Miami-Dade County in 1991. These rules limit vessel speed and, in some areas, entry. The national park also has slow-speed zones. Damaging seagrass inside the aquatic preserve can bring a fine of up to $1,000. Most of the park's waters are very shallow.