Mazama nemorivaga occurs in Brazil, French Guiana, Suriname, Guyana, Venezuela, Colombia, Isla San José (Panamá), Ecuador, Peru, and probably in Bolivia. In Brazil, this species occupies the Amazon forest and transitional areas in its border, where it may be in sympatry with M. gouazoubira as reported by Rossi (2000) for the states of Mato Grosso and Maranhão. It is probably present everywhere in the territory of French Guiana, Suriname, and Guyana, but in Venezuela it has a disjunct distribution that includes the evergreen and semidecidual forests south of Río Orinoco in the states of Amazonas and Bolívar, plus the decidual forests and xeric shrublands of the coastal region in the states of Aragua, Carabobo, Falcón, Lara, and Zulia (Bisbal 1991). In Colombia, Alberico et al. (2000) reported the occurrence of the Amazonian brown brocket deer in the Amazon and Caribbean regions in the states of Amazonas, Caquetá, Bolívar, Cesar, and Cundinamarca, from 0 to 500 meters high. Additional information gathered from the literature points the presence of this species also in the states of Antioquia, La Guajira, Magdalena, and Meta (Allen 1904; Barriga-Bonilla 1966; Lydekker 1915; Medellín et al. 1998; Osgood 1912). M. nemorivaga does not reach Central America except for the Isla San José in the Archipiélago de las Perlas, Golfo de Panamá, Panamá (Kellogg 1946; Medellín et al. 1998). In Ecuador, it can be found in the entire Amazon region (Tirira 2001). There is no published data regarding the distribution of M. nemorivaga in Peru, but according to J. Barrio (pers. comm.) this species occurs all over the Amazon region (except for some flooded areas), and reaches sites up to 1500 meters high (J. Barrio pers. comm.). It probably occurs in northern Bolivia, although Anderson (1997) had only reported the presence of M. g. gouazoubira in this part of the country.