Pumalín Park (Spanish: Parque Pumalín) is a 400,000 ha (988,422 acres) nature reserve in the Palena Province of Chile, created by the United States environmental foundation The Conservation Land Trust, which was endowed and led by the American business magnate Douglas Tompkins. Designated a Nature Sanctuary in 2005, Pumalín was Chile's largest private nature reserve and operated as a public-access park, with an extensive infrastructure of trails, campgrounds, and visitor centers. By an accord announced on 18 March 2017, the park was gifted to the Chilean state and consolidated with another 4,000,000 ha (9,884,215 acres) to become part of South America's largest national park.
The park consists of two areas, and there seems to be some interest of the park owners to purchase the intermediate 340 km² of the San Ignacio del Huinay Foundation as well. Opposed to this acquisition are mainly the thirty or so inhabitants of the hamlet Huinay, located at the coast of the aimed area. The northern portion of the park borders Hornopirén National Park.
In 1991, Douglas Tompkins bought a large, semi-abandoned plot of land in the Reñihue River Valley of the Chilean province of Palena. A mountaineer and conservationist who had been visiting Patagonia since the early 1960s, Tompkins sought to protect the 16,996.6 ha (42,000 acres) tract, most of which was primeval Valdivian temperate rainforest, from future exploitation. After moving to Reñihué to live full-time, Tompkins began developing plans for a larger park, gradually acquiring additional adjacent properties from willing sellers. Ultimately, roughly 98 percent of the park acreage was bought from absentee landowners.
The Conservation Land Trust subsequently added approximately 283,280 ha (700,000 acres) in nearly contiguous parcels to form Pumalín Park, which was declared a Nature Sanctuary on August 19, 2005, by then-president Ricardo Lagos. This special designation by the Chilean government grants the land additional protections to secure its ecological values and prevent development. The Conservation Land Trust later donated the protected lands to Fundación Pumalín, a Chilean foundation, for their administration and ongoing preservation as a national park under private initiative.