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) [XC192115]
by Ryan P. O'Donnell from Lafayette, Boulder, Colorado, United States (call)
Swainson's Hawk (Buteo swainsoni) [XC771857]
by Pedro Rinaldi from Whitewater Draw WA, near McNeal, Cochise Co, Arizona, United States (begging call, call)