Parque Nacional (PN) Toluaca is one of Chile's older national parks, founded in 1935. In Mapudungún, the Mapuche language, Tolhuaca means "cow's forehead." This reserve protects 6,474 hectares of Andean precordillera (foothills) and the headwaters of the Río Malleco, which borders the north edge of the territory. The landscape is shaped by the ancient activity of Volcán Tolhuaca (2806 m/9120 ft), located to the southeast, between PN Tolhuaca and Reserva Nacional (RN) Malacahuello-Nalcas. Rivers, streams and ravines are carved into the earth. The park's altitude ranges from 1000 to 1821 meters (3250-5919 feet).

High zones are covered by pure araucaria (monkey-puzzle tree, Araucaria araucana) forest. The lower altitudes have tineo (Weinmannia trichosperma), coigüe (Nothofagus dombeyi), olivillo (Aextoxicon punctatum), tepa (Laurelia philippiana), raulí (Nothofagus alpina), roble (Nothofagus oblicua), canelo andino (Drimys andina ) and chilco (bush fuchsia, Fuchsia magellanica). Underbrush, or sotobosque, consists of guindo santo (Chilean eucryphia, Eucryphia glutinosa), radal enano (Orites myrtoidea) and other plants.

Many mammal species are present in PN Tolhuaca, such as pudú (Chilean miniature deer, Pudu pudu), zorro gris (South American grey fox, Psuedolopex griseus), zorro culpeo (Patagonian fox, Lycalopex culpaeus) and chingue (Molina's hog-nosed skunk, Conepatus chinga). Coipo (nutria, Myocastor coypus) is the most common resident, especially in the Laguna Malleco area. Some birds to be seen are Cachaña (Austral parakeet, Enicognathus ferrugineus), Torcaza (Chilean pigeon, Patagioenas or Columbo araucana) and Condor (Vultur gryphus) and Pato Jergón Chico (speckled teal, Anas flavirostris). Also keep an eye out for the Hortensis butterfly fluttering by.

PN Tolhuaca has a cold temperate climate. The annual mean temperature is 14°C (57°F). The park receives regular, abundant rains, 2500-3000 mm (98-118 in) per year, with a dry period lasting about two months.

Parque Nacional Tolhuaca has a network of trails to be explored:
Sendero Chilpa (Distance: 1.5 km/0.9 mi, difficulty: medium, duration: 1.5 hours) –This trail, which begins off the Curacautín road, goes through araucaria and lenga forest and provides views of the Valle Anino.
Sendero Tolhuaca-Niblinto (12 km/7.2 mi, difficulty: medium, duration: 4 hours) – Accessed from the Laguna Malleco entrance, it begins at Prado Mesacura and ends at the administration office of the Reserva Nacional Malleco to the northeast; camping.
Salto Malleco (Distance: 1.7 km/1 mi, difficulty: easy, duration: 1 hour) – This path has 13 interpretive stations and leads to Sallto Malleco, a 49-meter (160-ft) high waterfall. Tagua, pimpollo, Pato Rana, Pata Jergón and Pato Real can be spotted.
Prados de Mescura (Distance: 15 km/9 mi, difficulty: medium, duration: 3 hours) – From the Laguna Malleco entrance, the trail cuts through araucaria forest, and glens to Guardería Prado west-northwest of Malleco. Features include natural miradores and the Río Pichi Malleco. Take drinking water.
Lagunillas (Distance: 12 km/7.2 mi, difficulty: medium, duration: 1 day) – From the Laguna Malleco entrance, this sendero weaves back and forth between PN Tolhuaca and RN Malleco. It reaches an altitude of 1645 meters (5346 ft) before arriving to Las Lagunillas whose crystalline waters are surrounded by araucaria. Condor is common.
La Culebra – Lago Verde (Distance: 2.1 km/1.25 mi difficulty: medium, 1.5 hours) – Beginning at the La Culebra entrance near Curacautín, it passes by Salto de la Culebra waterfall, through dense woods and ends at Lago Verde. Along the way are several lookout points over the Laguna Verde and Río Malleco Valleys. There are some short, steep sections.
Laguna Verde (Distance: 4 km/ 2.4 mi, difficulty: medium, duration: 2 hours) – This trail edges the south boundary of the park, from Laguna Malleco to La Culebra. Highlights include a small waterfall, the Colomahuida box canyon and araucaria-lenga forest.

After spending a day of hiking on the trails, relax in the Termas de Tolhuaca, located just outside the park on the road to Curacautín.

Entry into the park is: adults $4 (Chileans), $6 (foreigners); senior citizens $2 (Chileans), $3 (foreigners); children $0.80 (Chileans), $3 (foreigners).

Camping
Within the park are campsites at the Laguna Malleco entrance and along the Sendero Tolhuaca Niblinto trail. To pitch your tent costs, from January 1-February 28, $14 for Chileans and $24 for foreigners. The rest of the year, the fee is $8 (Chileans) and $10 (foreigners). No other services exist within the park. You must bring all food and water supplies (or water treatment).

Conaf in Temuco has a brochure of PN Tolhuaca with a topographical map. Another free bilingual pamphlet-map, entitled Guía Senderos / Araucanía Trails, has GPS coordinates for Tolhuaca and other regional national parks. Check for current road and weather conditions with Conaf or the carabineros.