Guaiba River
General data
- Name: Guaiba River
- Water system: Lagoa dos Patos
- Water type: River
- Progression: Lagoa dos Patos -> Rio Grande Channel -> Atlantic Ocean -> Planet Earth
- Climates: Tropical
- Continents: South America
- Countries: Brazil
Guaíba (Portuguese pronunciation: [ɡwaˈibɐ]) is a major water body in Rio Grande do Sul, the southernmost state of Brazil. It is commonly referred to either as a "river" (Portuguese: Rio Guaíba) or as a "lake" (Lago Guaíba). The Jacuí River, the Sinos River, the Gravataí River and the Caí River empty into Guaíba from the north, which in its turn empties into the Lagoa dos Patos, the largest lagoon in South America further down south. The body of water covers 496 square kilometres in total.