Argentina, Belize, Bolivia, Brazil, Canada (B), Colombia, Costa Rica, Ecuador, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Uruguay (NB), USA (B), Venezuela.
Vagrant to Chile, Dominican Republic, Norway, Trinidad and Tobago.
Western and central North America from Alaska south-east to Minnesota, and south to northern Mexico. Winters mostly in South America, especially in northern Argentina, southern Brazil and Paraguay; also some birds in southern and western USA.
 
Population
Estimated population is 490,000 (2010).
Swainson's Hawk (Buteo swainsoni) [XC438511]
by Bruce Lagerquist from Pawnee National Grassland (near Ault), Weld County, Colorado, United States (call)
Swainson's Hawk (Buteo swainsoni) [XC346459]
by Jim Holmes from Rodeo, Hidalgo County, New Mexico, United States (call)