Patagonia, semiarid scrub plateau that covers nearly all of the southern portion of mainland Argentina . With an area of about 260,000 square miles (673,000 square kilometres), it constitutes a vast area of steppe and desert that extends south from latitude 37° to 51° S. Patagonia , semiarid scrub plateau that covers nearly all of the southern portion of mainland Argentina . With an area of about 260,000 square miles (673,000 square kilometres), it constitutes a vast area of steppe and desert that extends south from latitude 37° to 51° S. It is bounded, approximately, by the Patagonian Andes to the west, the Colorado River to the north (except where the region extends north of the river into the Andean borderlands), the Atlantic Ocean to the east, and the Strait of Magellan to the south; the region south of the strait— Tierra del Fuego , which is divided between Argent...