Comodoro Rivadavia, often shortened to Comodoro, is a city in the Patagonian province of Chubut in southern Argentina, located on the San Jorge Gulf, an inlet of the Atlantic Ocean, at the foot of the Chenque Hill. Comodoro Rivadavia is the most important city of the San Jorge Basin, and is the largest city in Chubut as well as the largest city south of the southern 45th parallel.