Its operations and the majority of its reservation land are located in California, United States. The federally recognized Quechan tribe's main office is located in Winterhaven, California. Members are enrolled into the Quechan Tribe of the Fort Yuma Indian Reservation. Despite their name, they are not related to the Quechua people of the Andes. The Quechan ( Quechan: Kwatsáan 'those who descended'), or Yuma, are a Native American tribe who live on the Fort Yuma Indian Reservation on the lower Colorado River in Arizona and California just north of the Mexican border. Yumas in 'United States and Mexican Boundary Survey.