Patagonia (Spanish pronunciation: pataˈɣonja) is a sparsely populated region located at the southern end of South America, shared by Argentina and Chile. The region comprises the southern section of the Andes mountains as well as the deserts, pampas and grasslands east of this southern portion of the Andes. Patagonia has two coasts: western facing the Pacific Ocean and eastern facing the Atlantic Ocean.

The Colorado and Barrancas rivers, which run from the Andes to the Atlantic, are commonly considered the northern limit of Argentine Patagonia. The archipelago of Tierra del Fuego is sometimes included as part of Patagonia. Most geographers and historians locate the northern limit of Chilean Patagonia at Reloncaví Estuary.