Mogi Guaçu is a municipality in the state of São Paulo in Brazil. The population is 153,033 (2020 est.) in an area of 813 km2 (314 sq mi).[2] The city is at an average elevation of 591 m (1,939 ft) above sea level. Mogi Guaçu is a place name that probably originates from the Tupi language. It means "large river of snakes".[3] The city was founded on April 9, 1877. The municipality contains the 469 hectares (1,160 acres) Mogi-Guaçu Biological Reserve, a fully protected conservation area created in 1942.[4]