. . "For the river in Brazil, see S\u00E3o Francisco River. For the river in Argentina, see San Francisco River (Argentina). In Ecuador, the R\u00EDo San Francisco is a tributary of the Zamora River in Zamora-Chinchipe province.The San Francisco River is a 159-mile-long (256 km) river in the southwest United States, the largest tributary of the Upper Gila River. The river originates in Arizona and flows into New Mexico before it curves around and enters the Gila down stream from Clifton, Arizona."@en .