reaching all the way to the costa verde regionin the south of the state of rio, the sand bar creates about seventy-nine square kilometers of beach area. at the entrance of the sepetiba bay, marambaia faces ilha grande(the big island). the highest peak of the sandbar is pico marambaia, which elevates 647 meters above the sea.

in the language of the tupi, the original inhabitants of this region, the word 'mba-ra-mbai' or 'mbara-mbai' meant enclosed waters, referring to the sepetiba bay - characterized by calm waters as opposed to the wild waves of the rest of the coast facing the atlantic ocean.