Muntjac Taiwan and Southern China. They are also found in the lower Himalayas (Terai regions of Nepal and Bhutan) and in some areas of Japan (the Bōsō Peninsula and Ōshima Island). They have been introduced to Britain and Ireland. A large invasive species population of barking deer exists in the United Kingdom. Reeves's muntjac has been introduced to the United Kingdom, with wild deer descended from escapees from the Woburn Abbey estate around 1925. Muntjac have expanded very rapidly, and are now present in most English counties and have also expanded their range into Wales, although they are less common in
Reeves's muntjac species except where already established. Colonies exist throughout England south of Derbyshire, and the population continues to grow. In Ireland, sightings in 2008 caused the government, concerned at the risk of the species becoming established, to quickly introduce a year-round hunting season. In the 1960s, several specimens escaped from an exhibition zoo in the Bōsō Peninsula in eastern Japan. By 2017, their numbers had reached at least 60,000. It is considered a harmful invasive species and has inflicted severe damage to ashitaba plantations. Also, Reeves's muntjac escaped a zoo on Izu Ōshima in 1970 when a fence fell due to