Pampas, a grassy plains region of southern South America, covering parts of Argentina, Uruguay, and Brazil. The term pampas—from the Quechua Indian word for “plains"—is generally used only for Argentina. Although the land seems level, it slopes gradually from 2,000 feet (610 m) above sea level in the west to almost sea level on the Atlantic coast. The Argentine portion, by far the largest, covers about 250,000 square miles (647,500 km2). The eastern part, with 20 to 40 inches (508 to 1,016 mm) of annual rainfall, is an area of long grass, similar to the prairie region of the eastern Great Plains of North America. The western part is dry, with 3 to 20 inches (76–508 mm) of annual rainfall, and it has short grass and scrubby trees.

From its early history the region was used as grazing land, but in the 20th century great areas were put under cultivation. Corn and wheat now exceed livestock in value. The Pampas are the center of Argentina's population and economy, and the capital city, Buenos Aires, is there.