As one of the fundamental units of ecology and biogeography, the geographic distribution of the endemic and threatened ebony leaf monkey Trachypithecus auratus (E. Geoffroy Saint-Hilaire, 1812) on the islands of Java, Bali, and Lombok (Indonesia) has been assessed. All localities where the species has been collected are listed, and forty-two areas (each in itself consisting of numerous smaller sites) where the species has been recorded are discussed. The species occurs in a large variety of forest types, including mangrove, beach, and freshwater swamp forest; everwet lowland and hill forest; dry decidious forest; montane forest up to 3,000 - 3,500 m a.s.l.; and in some forest plantations (teak Tectona grandis, rasamala Altingia excelsa, acacia Acacia spp). In East Java, certain populations are dimorphic, containing, besides the more common melanic individuals, also erythristic individuals. This erythristic pelage morph only occurs in the easternmost part of Java of which the line between Mt. Penanggunang and the surroundings of Mojokerto running south-wards, via Wonosalam and Blitar, to Mts Kidul roughly forms the western boundary. Localities where individuals of the erythristic pelage morph have been collected or observed are given.