 The city has the highest rainfall of any in Brazil, with an annual average of .Calçoene is noted for its ancient megalithic observatory, often referred to as the "Amazon Stonehenge".Calçoene is bordered on the north and east by the Atlantic Ocean, to the south by the municipalities of Amapá and Pracuúba, and to the west by the municipalities of Oiapoque and Serra do Navio.