Pu Luong Nature Reserve protects 17,662 hectares of limestone karst and primary forest in the northwestern highlands of Thanh Hoa Province, about 150 kilometers from the provincial capital. The terrain is dramatic: two parallel ridges of contrasting character, one of rounded forested hills and one of heavily dissected limestone karst, with valleys running between them where Thai and Muong communities farm wet rice terraces.
The reserve is most visited as part of a 4–6 day trekking circuit from Hanoi via Mai Chau, staying with local families in traditional stilt houses along the route. The walking is moderately difficult — more about terrain and distance than technical climbing — and guides are essential for navigation. The best seasons are October to December and March to April; July and August bring heavy rain and leech-thick trails. Wildlife besides the leaf monkey includes serow, small carnivores, and over 160 bird species.