Breeds western Canada (northern British Columbia east to south-western Saskatchewan) southern in western USA (mainly west of Rocky Mts) to southern California and north-eastern New Mexico. Winters south-western USA (east to western Texas) and Mexico (S, mainly in highlands, to Oaxaca).
 
Population
Estimated population is 3,600,000 (2010).
American Dusky Flycatcher (Empidonax) [XC769225]
by Tayler Brooks from Leslie Canyon National Wildlife Refuge, Cochise County, Arizona, United States (call)
American Dusky Flycatcher (Empidonax oberholseri) [XC653500]
by Paul Marvin from Henness Pass Rd, Sierra County, California, United States (song)
Subspecies
No subspecies.
Formerly considered conspecific with American Grey Flycatcher (Empidonax wrightii), although appears not to be closely related.