🇦🇷 Argentina · The Northeast
Río Pilcomayo National Park protects one of the most representative landscapes of the humid Chaco, in the far northeast of Formosa province, on the border with Paraguay. It's a mosaic of marshes, lagoons, grasslands, caranday palm savannas and woodland, home to abundant wildlife and dazzling birdlife, in one of the least travelled and most authentic regions in the country.
Created to conserve this unique environment, the park lets the visitor get into the humid Chaco and watch caimans, capybaras, howler monkeys, maned wolves, waterbirds and an enormous diversity of wildlife, all in a setting of great beauty and solitude. It's a destination for lovers of nature, birdwatching and protected-area travel, far from the crowds.
This guide covers the essentials of Río Pilcomayo National Park with a practical eye: its two public-use areas — Laguna Blanca and Estero Poí — its trails and lookouts, the wildlife and plants you can see, the free access, and how to reach and get around this corner of the Formosa Chaco, a natural treasure of northeastern Argentina.
Río Pilcomayo National Park was created by Law 14.073 of 1951 to protect a representative sample of the eastern humid Chaco, an environment of marshes, lagoons, savannas and woodland of great biological richness. It was born with 285,000 hectares and was reduced in 1968 to the current 51,889. Its name comes from the Río Pilcomayo, which marks the northern boundary of Formosa province and of Argentina with Paraguay. Since 4 May 1992 it has been a Wetland of International Importance (a Ramsar site), one of the first in Argentina. The full story is on our history page.
Read the full history ↓The province of the far north, between the Pilcomayo and the Bermejo: Qom, Wichí and Pilagá land, defined by the Hayes Award of 1878, marked by the Rincón Bomba Massacre of 1947, of marshes, palm groves and the Bañado La Estrella, one of the last natural frontiers in the country.
Read the history of Formosa →No exact prices: a scale from $ (budget) to $$$$$ (luxury), with 2-3 options per category.
Origins, formation and what the sources say.
There's a river in South America that carries so much sediment it buries itself: the Pilcomayo, which comes down from the Bolivian Andes loaded with sand and silt, loses its channel on the Chaco plain and spreads out into floodplains, marshes and lagoons that shift position over the years. It's one of the few great rivers in the world that doesn't arrive whole at its destination — much of its water evaporates or seeps into the Chaco — and that anarchic behaviour created, in the far northeast of Formosa, the wetland paradise that Río Pilcomayo National Park protects today.
The park lies in the eastern humid Chaco, a strip of the great Chaco plain where the rains — more than 1,200 mm a year — and the rivers overflowing generate a mosaic of marshes, lagoons, caranday palm savannas and woodland. It's a transition environment of enormous biological richness, shaped by water and the subtropical climate: the same river that gives the park its name marks Argentina's border with Paraguay here.
This territory was, for millennia, the home of the Indigenous peoples of the Chaco and a region that was hard to reach, which helped preserve its natural character. Its ecological value — as a sample of the humid Chaco and as a wildlife refuge — would be the reason that, in the mid-20th century, led to it being protected as a national park.
Río Pilcomayo National Park was created by Law 14.073, passed on 29 September 1951, as part of the expansion of the Argentine national park system that sought to protect representative samples of the country's different environments. While the first parks had concentrated on the Patagonian Andes and the Iguazú falls, the creation of Río Pilcomayo answered the need to conserve the ecosystems of the north and the Chaco as well, until then barely represented.
The original park was a giant: it covered some 285,000 hectares of northeastern Formosa. But in 1968, pressure for productive use of the land led to a drastic reduction to the current 51,889 hectares, less than a fifth of the initial area. Even so, the conserved area shelters a typical stretch of the eastern humid Chaco, with its marshes, lagoons, palm groves and woodland, and the associated wildlife, in a region where the advance of farming, ranching and logging (especially of quebracho) transformed almost all the surrounding landscape. The park thus became a refuge for threatened species and a record of what the region once was.
International recognition came on 4 May 1992, when its wetlands were declared a Wetland of International Importance under the Ramsar Convention — one of the first Ramsar sites in Argentina. Over time, the park was organized into two public-use areas — Laguna Blanca and Estero Poí — that let visitors get to know its environments without compromising their conservation, under the management of the National Parks Administration and the daily work of the rangers.
Río Pilcomayo National Park plays a fundamental role in conserving the biodiversity of the humid Chaco, one of the country's most threatened regions because of the advance of the farming frontier and deforestation. Numerous species find refuge within its boundaries, among them emblematic and threatened mammals such as the maned wolf — the great maned canid of the marshes — the giant anteater, the giant armadillo (the largest armadillo in the world) and various cats, plus the two caiman species (yacaré overo and yacaré negro), capybaras, howler monkeys and a diverse Chaco fauna. Laguna Blanca, with its shallow, warm water, concentrates one of the most visible caiman populations in the country: seeing them sunning themselves next to the walkways is close to guaranteed.
The park is especially known for its birdlife: the combination of aquatic and land environments makes it one of Argentina's great birdwatching destinations, with around 300 species recorded, from herons, storks and southern screamers to the rhea and the savanna birds of prey. That richness has made it valued both by the scientific community and by birdwatchers worldwide, and explains its designation as a Ramsar site in 1992.
In recent decades, the park has been folded into Formosa province's nature tourism offering, alongside other attractions such as the Bañado La Estrella. Its remote, uncrowded character is precisely part of its appeal: it offers an immersive experience of the deep Chaco, with the chance to watch wildlife in freedom and to get to know an environment that, outside protected areas, is increasingly under threat. In that sense, Río Pilcomayo is living testimony to the value of conserving the nature of northern Argentina.
The region where the park now stands was, for millennia, the territory of Indigenous peoples of the Gran Chaco, especially the Qom (Toba), the Pilagá and the Wichí, hunter-gatherer and fishing communities who lived in close relationship with the rivers, the marshes and the woodland. The Río Pilcomayo and its floodplains were a source of fish, water and resources, and they structured the life of these societies, which knew the water cycles and the wildlife of the region inside out.
These peoples developed a deep knowledge of the Chaco environment: the useful plants, the behaviour of the animals, the timing of the floods. Their way of life, adapted to a demanding and changeable setting, left a cultural mark that lasts to this day in the Indigenous communities of Formosa, many of whom live near the park.
Colonization, the advance of the farming frontier, the logging of quebracho and the consolidation of the Argentine state in the region, between the late 19th and the 20th centuries, drastically transformed this territory and the lives of its original inhabitants, in a process that was often violent. By conserving a sample of the humid Chaco in its natural state, the national park also preserves the ancestral landscape these peoples inhabited for thousands of years.