Matanzas River

The Matanzas River is a narrow, saltwater, bar-bounded estuary in St. Johns and Flagler counties, Florida. Anastasia Island shelters it from the Atlantic Ocean, and it forms part of the Atlantic Intracoastal Waterway. It runs about 23 miles, from St. Augustine Inlet south to roughly 6.5 miles past Matanzas Inlet at the southern tip of Anastasia Island. Because it lies between these two ocean inlets, it is tidal and does not flow in a single direction, with a tidal range of up to 6 feet. Three major bridges cross it: the Bridge of Lions, the Mickler-O'Connell Bridge and the Crescent Beach Bridge (State Road 206).

St. Johns County operates several public ramps on the river. Green Road Boat Ramp serves both the Matanzas River and the Intracoastal Waterway and has a fishing dock and limited street parking. Palmetto Boat Ramp has a single ramp for small private craft and a small fishing dock, and is open from sunrise to sundown. Douglas C. Crane Boat Ramp, at 1039 Shore Drive, is for small boats and kayaks. Frank B. Butler Park West also has a ramp. Carry-in access includes Helen Mellon Schmidt Park, Coastal Drive Kayak Beach and the Matanzas Inlet west parking lot at Fort Matanzas National Monument.

The river was the main entrance to St. Augustine. In the 18th century, Spanish builders put up Fort Matanzas to control access from Matanzas Inlet. The name, Spanish for "killings," refers to the 1565 execution of shipwrecked French Huguenots near the inlet. Protected tidal marsh along the river includes the Guana Tolomato Matanzas National Estuarine Research Reserve.