This species is endemic to Sri Lanka. Four subspecies have been recognized.
The conservation status of this species is regarded as Endangered (National Red List 2012). It is a species protected under the Fauna and Flora Protection Ordinance as amended by Act No. 22 of 2009.
In forests Purple-faced Leaf Monkeys are usually found in troops of 10-15 animals with a large male being the leader. The loud call of the dominant male is a familiar sound to the people who live in most wet zone villages. Despite much development and human activity that has taken place during the last two decades, Talangama wetlands is a location very close to the city of Colombo where these playful monkeys can still be observed.
The western race of this interesting species found in areas close to the city of Colombo is the most vulnerable of all the subspecies due to loss of habitat. In 2011 a population comprising of a few troops of leucistic Southern Purple-faced Leaf Monkeys were discovered from the southern rainforests close to Deniyaya. Phillips in 1926 in reported on such an occurrence of colour in Purple-faced Leaf Monkey as well.
The subspecies that is found in Wilpattu is the Northern Purple-faced Leaf Monkey and is one location where this species lives along with its cousin the Tufted Grey Langur Semnopithecus priam. Unlike the Toque Monkey Macaca sinica seen at Kumbuk Wila this species is quite shy and is difficult to photograph at Wilpattu. I have seen them at Eluwankulama, Pomparippu, Maradanmaduwa, Palu Kola Wala and at Ibba Wala.