The Carioca River (Portuguese: Rio Carioca) is a river in the state of Rio de Janeiro state in southeastern Brazil. It emerges from two springs on the southeast slopes of the Tijuca Massif in the protected Mata Atlantica forest of Tijuca National Park. The river then leaves Tijuca Forest into the Guararapes favela, then into the high-income Cosme Velho neighborhood, and then it is buried completely underground. The river reemerges in Flamengo Park to empty into Guanabara Bay at .