The Paraguayan Chaco is a region within the Gran Chaco, which is South America's second-largest forest. This area covers 23% of Paraguay's land, which is about 1 million square kilometers. The Paraguayan Chaco is the largest area in Paraguay and can be divided into two parts: the Dry Chaco in the northwest, which has forests that grow in areas with uneven rainfall, and the Humid Chaco, which includes dry forests, grasslands with palm trees, and wetlands that flood seasonally.

Geologically, the Great South American Chaco is a flat plain. It formed millions of years ago, closely linked to the creation of the Andes Mountains and the erosion that followed. Originally, the Chaco was a basin that gradually filled with sediments carried by wind and by rivers that transported and deposited materials into the region.

The Paraguayan Chaco faces dangers such as cutting down trees, wildfires, and hunting of animals. By 2030, it is predicted that half of the forest area may be lost due to cattle farming and soybean farming, according to the World Land Trust.

Environmental impacts

• Using red quebracho trees (Schinopsis balansae and Schinopsis lorentzii) for the tannin industry during the 19th and 20th centuries
• Mennonite communities moving to live in the Central Chaco starting in the 1920s
• The Chaco War between Paraguay and Bolivia (1932–1935)
• Searching for oil in the region
• Building and paving roads, especially the Carlos Antonio López or Trans-Chaco highway (Route 9), Route 5 between Pozo Colorado and Concepción, and the Bioceanic Corridor
• Constructing bridges across the Paraguay River: Puente Remanso (Asunción-Villa Hayes) and the Nanawa bridge (Concepción-Puerto Militar)
• Establishing experimental agricultural stations

Protected areas

The park was created in 1998 and covers an area of 125,823 hectares. The River Timané is located in this area and is unique because it does not flow into any river or lagoon. Cerro Cabrera is on the border with Bolivia. The vegetation includes thick grasslands and open woodlands. Common trees are white quebracho, samuù, and palo santo. Animals found here include wild cats, armadillos, giant anteaters, and tapirs.

Choroveca National Monument was established in 1998 and covers 100,953 hectares. Its plant life is different from other areas of the Chaco and is considered unique in the country. The soil is reddish sand, typical of the Oriental Region, and is very shallow. The area is known for its unique beauty, including bushes and tall forests where the endangered trebol tree (Amburana cearensis) grows. Animals include yurumí (ant-eater), kaguaré, and other felines and armadillos.

Defensores del Chaco National Park is the largest protected area in Paraguay. It covers 720,000 hectares and was created by decree number 16.806 on August 6, 1975. The park includes a large plain with vegetation such as white quebracho, palo santo, samuù, low forests, thorny bushes, and various cacti. It is home to large mammals like jaguars, pumas, Geoffroy's cats, jaguarundis, armadillos, monkeys, peccaries, and tapirs. The park includes Cerro León, a special geological feature made of hills. To reach it, travelers can take a 177 km road from Mcal Estigarribia to Gral P Colman, then continue to Lagerenza (north) or to Cerro León and Madrejon.

Médanos del Chaco National Park covers 514,233 hectares. It was originally part of the Paraguayan Wildlands Project (supported by the Global Environment Facility of the UN). The park is known for its "médanos" or dunes and their unique plant life, as well as guanacos. Park rangers operate from the nearby Teniente Agripino Enciso National Park.

A park was created in 1998 with an initial area of 30,000 hectares. It was expanded in 2004 to cover 123,789 hectares. It protects ecosystems typical of the Pantanal and the Humid Chaco. The area includes regularly flooded regions and Karanda'y palm trees. It was declared a Ramsar Site in 1995 because it supports migratory birds and other wetland species. Animals include jaguars, wild parrots, Pantanal deer, lobope, and yacares. The park does not yet have a formal plan or tourism facilities. To reach it, travelers can use the Lagerenza-Bahia Negra road or travel through Defensores del Chaco National Park.

Teniente Agripino Enciso National Park was created in 1980 and covers 40,000 hectares. Its rectangular shape helps protect biodiversity. The area has typical landscapes of the Dry Chaco, with vegetation dominated by dense, hard-to-pass thorny forests. Common trees include white quebracho, palo santo, and samuù. The park is home to many wild mammals, such as felines (including yaguarte), peccaries (with tagua as the area’s symbol), and trenches and paths from the Chaco War. Park guards, trained to assist visitors, lead tours of these historical sites.

A park was created in 1996 as a national park covering 280,000 hectares. It is now recommended to change its status to a resource reserve because its entire area is privately owned, and national parks must be public and protected. The Tinfunque was declared a Ramsar Site and is listed as an area of international wetland importance. It is located in a region that remains flooded during high water levels of the Pilcomayo River and has large natural grasslands. The area has shrubs adapted to flooding and supports animals like ñandy, wild ducks, storks, chaja, aguara guazu, giant anteaters, carpincho, and yacares. Conservation depends on wildlife and cattle coexisting in the same space. Visitors often see ñandy and carpincho sharing water with cattle. To reach it, travelers can take the Transchaco road for 180 km, then turn west at Pozo Colorado to Fortín General Diaz.