South-western Canada (central and eastern British Columbia and south-western Alberta) and western USA in Rocky Mts and Sierra Nevada (Washington to California and east to Wyoming and western Colorado). Winters in west-central and south-central Mexico (south-eastern Sinaloa to east-central Oaxaca).
 
Population
Estimated population is 1,000,000 (2010).
Calliope Hummingbird (Selasphorus calliope) [XC147299]
by Ian Cruickshank from Beatty's in Miller Canyon (near Hereford), Cochise Co, Arizona, United States (flight call)
Calliope Hummingbird (Selasphorus calliope) [XC103107]
by Eric DeFonso from Carman Valley, Sierra County, California, United States (song)
Subspecies
Genus sometimes merged into Mellisuga. Alternatively lumped into Archilochus.
Proposed subspecies lowei (Guerrero) based on a winter specimen, and claimed differences fall within normal variation.