Mogi Guaçu is a municipality in the state of São Paulo in Brazil. The population as of 2008 was 141,559 people and these covered an area of 885.00 km². The city is at an average elevation (above sea level) of 591 m. Mogi Guaçu is a place name that probably originates from the Tupi language. It means "large river of snakes"..