Maullin is a town situated on the Río Maullín in the Los Lagos Region of Chile.

The river itself originates at Lago Llanquihue and travels approximately 85 kilometers in a generally southwestward direction before emptying into the Gulf of Coronados as a tidal estuary.

With a drainage basin of nearly 3,972 square kilometers and an average flow of 73 cubic meters per second, the river is a significant waterway in the region.

The surrounding wetlands and estuary are notable for their exceptional biodiversity, particularly aquatic and coastal bird species.

Laguna Quenuir, within the estuary, is recognized as having the greatest diversity of bird fauna along this stretch of the Chilean coast, making the area of interest to wildlife observers and nature travelers passing through.