View of the Matanzas Bay from the Castillo de San Marcos

Matanzas Bay is a saltwater bay in

St. Johns County, Florida St. Johns County is a county in the northeastern part of the U.S. state of Florida. As of the 2020 United States census, its population was 273,425. The county seat and most populous incorporated city is St. Augustine, although the nearby c ...

; the entrance to the bay from the

South Atlantic The Atlantic Ocean is the second largest of the world's five oceanic divisions, with an area of about . It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for ...

is via St. Augustine inlet. Technically this stretch of water running along the city's waterfront is part of the Matanzas River, though it is regularly referred to as a bay or harbor. Bodies of water that connect to the bay in addition to the South Atlantic are clockwise from the inlet: *Salt Run: an inlet of

Anastasia Island Anastasia Island is a barrier island located off the northeast Atlantic coast of Florida in the United States. It sits east of St. Augustine, running north–south in a slightly southeastern direction to Matanzas Inlet. The island is about lon ...

creating a

peninsula A peninsula is a landform that extends from a mainland and is only connected to land on one side. Peninsulas exist on each continent. The largest peninsula in the world is the Arabian Peninsula. Etymology The word ''peninsula'' derives , . T ...

of the eastern portion of

Anastasia State Park Anastasia State Park is a state park in Florida, United States. Its location is on a peninsula on Anastasia Island across Matanzas Bay from downtown St. Augustine along the Atlantic coastal plain. This park has a variety of wildlife, birds an ...

. *

Matanzas River The Matanzas River is a body of water in St. Johns and Flagler counties in the U.S. state of Florida. It is a narrow saltwater bar-bounded estuary sheltered from the Atlantic Ocean by Anastasia Island. The river is part of the Atlantic Intraco ...

: a tidal channel; part of the

Intracoastal Waterway The Intracoastal Waterway (ICW) is a Navigability, inland waterway along the Atlantic and Gulf of Mexico coasts of the United States, running from Massachusetts southward along the Atlantic Seaboard and around the southern tip of Florida, the ...

which flows in an easterly direction then south for approximately 15 miles, separating Anastasia Island from the mainland. Another tidal channel the San Sebastian River flows westerly from the Matanzas River creating a peninsula of the original Spanish era section of St. Augustine. *Hospital Creek: tidal channel flowing north from confluence of Matanzas Bay and North River. Creek in which

Pedro Menéndez de Avilés Pedro Menéndez de Avilés (; ; 15 February 1519 – 17 September 1574) was a Spanish admiral, explorer and conquistador from Avilés, in Asturias, Spain. He is notable for planning the first regular trans-oceanic convoys, which became known as ...

sailed into and initially established St. Augustine on its mainland shore. *

Tolomato River The Tolomato River is a river in St. Johns County, Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northw ...

(also known locally and historically in the British period as the North River): tidal channel flowing north Inside route pilot By U.S. Coast and Geodetic Survey, Leon Archie Potter, Herbert Cornelius Graves p. 70 *Municipalities:

St. Augustine Augustine of Hippo ( , ; ; 13 November 354 – 28 August 430) was a theologian and philosopher of Berber origin and the bishop of Hippo Regius in Numidia, Roman North Africa. His writings deeply influenced the development of Western philosop ...

and Vilano Beach. *Tides: The average fall of the tides in Matanzas Bay is 4.5 feet between high and low tide. *Bridges: State road A1A crosses the bay via the

Bridge of Lions The Bridge of Lions is a double-leaf bascule bridge that spans the Intracoastal Waterway in St. Augustine, Florida, United States. A part of State Road A1A, it connects downtown St. Augustine to Anastasia Island across Matanzas Bay. A pair ...

which connects the mainland portion of St. Augustine with the portion of the city located on Anastasia Island. *Wetlands: A large portion of the tidal wetlands directly fronting the bay have been obliterated due to construction of the seawall in the old quarter of St. Augustine and the construction of Davis Shores a residential development created on reclaimed land on Anastasia Island and a subsequent seawall. The portions of the Intracoastal Waterway connected to Matanzas Bay have wetlands of varying amounts and degrees of natural state. *Parks:

Castillo de San Marcos The Castillo de San Marcos ( Spanish for “ St. Mark’s Castle”) is the oldest masonry fort in the continental United States; it is located on the western shore of Matanzas Bay in St. Augustine, Florida. It was designed by the Spanish en ...

National Monument, Spanish era fort completed in 1675 and

References

{{Coastal Waters of Florida St. Augustine, Florida Bodies of water of St. Johns County, Florida Bays of Florida on the Atlantic Ocean