Nalcas National Reserve, National reserve in Malleco Province, Chile.

Nalcas National Reserve is a protected area in the Araucanía region, in the Lonquimay commune, 180 km from Temuco, adjacent to Malalcahuello National Reserve and managed with it as a unit. The Tolhuaca and Lonquimay volcanoes lie on its boundaries. The Nalcas River runs 20 km through the reserve to the Lolco River, and the Laguna Grande de Nalcas, Chica, Verde and Holandesa lie within it.

Nalcas National Reserve lies in the Lonquimay commune of the Araucanía region, 180 km from Temuco, and is administered together with the adjacent Malalcahuello National Reserve as a single unit. Its boundaries take in the Tolhuaca and Lonquimay volcanoes, and the Nalcas River runs 20 km through the reserve before joining the Lolco River, one of its eastern limits.

The reserve lies in the Biobío basin, where the Nalcas River runs 20 km through the protected area before joining the Lolco River, one of its eastern limits. Four lagoons sit within the reserve: Laguna Grande de Nalcas, Chica, Verde and Holandesa. The Araucaria araucana and Cordilleran cypress growing here are listed as species with conservation problems.

Access to trails begins at Malalcahuello village, where CONAF rangers provide information and guidance before visitors head out. The steep mountain terrain requires sturdy footwear and caution, as paths can be muddy or slippery, especially after rain.

The reserve shares a boundary with Malalcahuello Reserve at the volcano Lonquimay summit, together forming one large combined protected zone. This arrangement allows wildlife to move freely between both areas, supporting healthier animal populations.