The Valdes Peninsula is a peninsula on the Atlantic coast in the Viedma Department in the north east of Chubut Province, Argentina. Around 3,625 km2 in size, it is an important nature reserve which was listed as a World Heritage Site by UNESCO in 1999.
The nearest large town is Puerto Madryn. The only town on the peninsula is the small settlement of Puerto Piramides. There are also a number of estancias, where sheep are raised.
Most of the peninsula is barren land with some salt lakes. The largest of these lakes is at an elevation of about 40 m below sea level, until recently thought to be the lowest elevation in Argentina and South America.