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) [XC578102]
by Richard E. Webster from Spanish Ranch, Plumas County, California, United States (song, mechanical display sound from dives)
Calliope Hummingbird (Selasphorus calliope) [XC412986]
by Bruce Lagerquist from Kinney Creek drainage,Pocatello, Bannock County, Idaho, 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.