This species is confined to a few areas in far northeastern Viet Nam (Groves 2001). Historically limited to areas east of the Red River (Nadler et al. 2003), its distribution has become dramatically restricted in recent decades due to massive deforestation and intensive hunting (Nadler et al. 2003). It is currently known only from small forest patches in Tuyen Quang and Bac Kan Provinces, and to a lesser extent in Ha Giang and Thai Nguyen Provinces (Nadler et al. 2003).