Southern Baja California; also Cerralvo I and perhaps sporadically on San José I (Gulf of California). Recent vagrant to southern California (USA), where attempted to nest.
 
Population
Estimated population is 20,000 - 49,999 (2010).
Xantus's Hummingbird (Basilinna xantusii) [XC21264]
by Richard E Webster from Comondu, Baja Sur, Mexico (flight call)
Xantus's Hummingbird (Basilinna xantusii) [XC21259]
by Richard E Webster from Rio Comondu below San Miguel, Baja Sur, Mexico (call)
Subspecies
Genus often merged into Hylocharis, though external morphology suggests closer relationship to Lampornis. Forms a superspecies with White-eared Hummingbird (Basilinna leucotis).