Belize, Costa Rica, El Salvador (B) (NB), Guatemala (B) (NB), Honduras, Mexico (B) (NB), Nicaragua.
Atlantic slope of south-eastern Mexico (including islands off Quintana Roo), northern Guatemala, Belize, and northern Honduras; also Pacific slope of El Salvador, and Nicaragua and northern Costa Rica.
 
Population
Estimated population is 50,000 - 499,999 (2010).
Black-headed Trogon (Trogon melanocephalus) [XC28355]
by Peter Boesman from Rio Bravo Research Area, Orange Walk Dist., Belize (song)
Black-headed Trogon (Trogon melanocephalus) [XC350440]
by Tuomas Seimola from The Lodge at Pico Bonito, El Pino, Atlantida, Honduras (call)
Subspecies
Forms a superspecies with Green-backed Trogon (Trogon viridis), Baird's Trogon (Trogon bairdii) and Citreoline Trogon (Trogon citreolus) and sometimes considered conspecific with Citreoline Trogon (Trogon citreolus). Populations of western Costa Rica described as subspecies illaetabilis on basis of paler belly, but this character apparently not constant.
The following 2 subspecies are recognised:
melanocephalus Gould, 1836 - South-eastern Mexico to northern Costa Rica.