The Pedra do Castanho I archaeological site is a large rock formation approximately fourteen meters high and over forty meters in circumference, resting on a granitic structure that emerges on the eastern side, over five meters in height. On its eastern portion, wind action has formed a cavity approximately two meters high and three meters deep. This space houses, to the north, a rock art panel five meters long, decorated with red and yellow pigments, mostly featuring representations of human figures depicting ritualistic movements, as well as two dugout canoes.