There is no information available that allows for the separation of the ranges of the A. juara of Brazil and Peru from A. seniculus of the Colombian Andes and Venezuela (type locality: Cartagena, Bolivar, near the Río Magdalena, Colombia), so they have been mapped together.

In Colombia, A. seniculus is absent from the Pacific and the desert of the Guajira Peninsula, and has not been reported in from the Department of Nariño (Hernández-Camacho and Cooper 1976; Defler 2004). Otherwise, it is present throughout the country, except in non-forested areas and mountainous regions above about 3,000 m above sea level (though it has been reported at 3,200 m in the Central Andes) (Hernández-Camacho and Cooper 1976). In Venezuela, Bodini and Pérez-Hernández (1987) indicate that the howler monkey north of the Rio Orinoco and west through Apure basin north of the Rio Meta the is a distinct, as yet undescribed, form, but Linares (1998) labeled it as A. arctoidea, otherwise also occurring along the north coast of Venezuela. Alouatta seniculus occurs west of the Sierra de Merida and aorund Lake Maracaibo.

In summary, Alouatta juara-seniculus occurs west of the of the rios Juruá and Envira through the Peruvian Amazon north (say) of the Rio Inuya, north along the Andean Cordillera into Ecuador and in Colombia including the Cordillera Central and the Cordillera Oriental into Venezuela around Lake Maracaibo, west of the Serra de Merida. It is possible that either an undescribed red howler (Bodini and Pérez-Hernández 1987) or A. arctoidea (Linares 1998) occurs north of the Rio Meta in Colombia.