This reserve covers a mountainous surface area of 31 260 hectares which incorporates the Lonquimay Volcano, 2 820 metres above sea level and the Tolhuaca Volcano, 2 806 metres above sea level. The following hills also jutt into the park; La Arenal, La Plancha and Las Raíces.

The vegetation is typical of the Andean high altitude forests with monkey puzzle trees,  Lenga beeches, Southern beeches, oaks and Raulí beeches. The vegetation also shelters a rich fauna consisting of pumas, chilla and culpeo foxes, slender-billed conure parrots, black woodpeckers and owls. 

A concessionary company is presently developing a tourism/sports complex in the skiing area on Lonquimay Volcano where you can go for walks, trips, horseback journeys at any time of the year.