Built in 1616 by the Portuguese to protect a city that had just been founded, the fortification is located on Ponta Maúri, at the confluence of Guaianá River and the Bay of Guajará, marking the entrance to the port and the navigation channel that runs alongside Onças Island in Belém.

Built with the purpose of defending the Amazon, especially from the prospect of a French invasion (the French had already occupied the territory of Guyana), it occupies a vast area on the left bank of the mouth of the Amazon River in the capital of Amapá.