Dusky Hummingbird is endemic to southwestern Mexico. This species occurs in the interior, from eastern Michoacán and Morelos south to Oaxaca (Friedmann et al. 1950, Binford 1985, 1989, Howell and Webb 1995). Friedmann et al. (1950) also reported specimens from the Distrito Federal and from Jalisco and Hidalgo; Howell and Webb (1985) regard the record from Distrito Federal as dubious, and also voice doubts that the records from Jalisco and Hidaldo are valid.
The elevational range of Dusky Hummingbird is 900-2200 m (Howell and Webb 1995).