It was built to monitor and secure the region against French, English, and Dutch incursions seeking brazilwood.
The structure is made of stone, lime, and whale oil, a common construction binder used in 17th-century colonial Brazil.
Its strategic position allowed for cross-fire protection of the Cabo Frio harbor entrance.
The site was listed as a national heritage monument by the National Institute of Historic and Artistic Heritage (IPHAN) in 1956.
The fortress occupies a rocky promontory that separates Praia do Forte from the smaller Praia das Dunas.
During the 17th century, the fort served as a residence for the military garrison tasked with regional surveillance.
Forte de São Mateus is a 17th-century fortification constructed between 1616 and 1620 to protect the Brazilian coastline from foreign invaders and pirates. Built on a rocky islet at the end of Praia do Forte in Cabo Frio, the structure showcases traditional colonial military architecture. The stone walls were erected during the period of the Iberian Union to defend the valuable brazilwood trade and salt pans. It features original cannons positioned along the ramparts facing the Atlantic Ocean. The fortress has undergone multiple restoration projects to preserve its masonry and historical integrity. It currently operates as an open-air historical site and local cultural landmark. The location provides a high vantage point overlooking the surrounding coastline and the Atlantic horizon.
From the base of the fort looking back toward the long curve of Praia do Forte during golden hour.
Wear footwear with a good grip, as the rocky terrain surrounding the fort can be uneven and slippery.
The area is highly exposed to the sun; bring hats and sun protection as there is minimal shade within the walls.
Visit during low tide to explore the rock formations around the base of the islet safely.
Do not attempt to walk along the narrow rocks surrounding the fort during high tide or heavy swell conditions.
Avoid climbing or sitting on the historical cannon mounts; maintain a respectful distance from the preserved masonry.
