Guanabara Bay is an oceanic bay located in Southeast Brazil in the state of Rio de Janeiro. On its western shore lie the cities of Rio de Janeiro and Duque de Caxias, and on its eastern shore are the cities of Niterói and São Gonçalo. Four other municipalities surround the bay's shores. Guanabara Bay is the second largest bay in area in Brazil, at 412 square kilometres (159 sq mi), with a perimeter of 143 kilometres (89 mi).