niterói shares the guanabara bay with rio de janeiro, as well as the municipalities of são gonçalo and duque de caxias.

the two most important islands in guanabara bay are part of rio de janeiro - the bucolic ilha de paquetá and the ilha do governador, home to the main international airport in the state of rio.

on the niterói side, there are a few inhabited islands but mostly used for military bases and installations, and not generally open to visits or to the public. 

one of them, ilha das enxadas (scuffle island), located halfway between the ilha das cobras and the bridge rio - niterói, is home toseveral brazilian navy installations -and it does have an historical part in the defense of rio de janeiro and the country in general.