South-eastern Sonora and south-western Chihuahua southern in Sierra Madre Occidental to western Zacatecas and northern Jalisco. Considered by some authors to be a subspecies of Ultramarine Jay (Aphelocoma ultramarina).
 
Population
Estimated population is 2,000,000 (2010).
Mexican Jay (Aphelocoma wollweberi) [XC297541]
by Ross Gallardy from Pinnacles Trail, Big Bend NP, Brewster Co. TX, United States (call)
Mexican Jay (Aphelocoma wollweberi) [XC408870]
by Leonardo Guzman Hernandez from Arteaga, Coahuila de Zaragoza, Mexico (call, song)
Subspecies
Considered by some authors to be a subspecies of Ultramarine Jay (Aphelocoma ultramarina).
The following 5 subspecies are recognised:
arizonae (Ridgway, 1874) - Southern USA (south-eastern Arizona and south-western New Mexico) south to northern Mexico (northern Sonora and north-western Chihuahua). Considered by some authors to be a subspecies of Ultramarine Jay (Aphelocoma ultramarina).
wollweberi Kaup, 1854 - South-eastern Sonora and south-western Chihuahua southern in Sierra Madre Occidental to western Zacatecas and northern Jalisco. Considered by some authors to be a subspecies of Ultramarine Jay (Aphelocoma ultramarina).
potosina Nelson, 1899 - East-central Mexico (San Luis Potosí south to central Hidalgo). Considered by some authors to be a subspecies of Ultramarine Jay (Aphelocoma ultramarina).
couchii (Baird, SF, 1858) - Extreme southern USA (Chisos Mts of extreme south-western Texas) southern in Sierra Madre Oriental to southern Nuevo León and northern San Luis Potosí. Considered by some authors to be a subspecies of Ultramarine Jay (Aphelocoma ultramarina).
gracilis Miller, GS, 1896 - Western Mexico (Nayarit and north-western Jalisco). Considered by some authors to be a subspecies of Ultramarine Jay (Aphelocoma ultramarina).