Rumblar Reservoir, A reservoir with a capacity of 126 cubic hectometres, located in Sierra Morena, next to the town of Baños de la Encina, province of Jaén, Spain.

Rumblar Reservoir is a large water storage facility in the river valley near Baños de la Encina in Jaén Province, extending across hundreds of hectares when full. The structure consists of a stone and concrete dam approximately 65 meters tall and 220 meters wide, which holds back and regulates the flow of water.

The reservoir takes its name from the Rumblar River, which forms within it where the Pinto and Grande rivers meet. Its shore partially covers the Argaric settlement of Peñalosa, about 4,000 years old, whose terraced streets, slate-walled rectangular houses and cistern lie partly under water; excavations there revealed metalworking remains and a monumental burial.

The reservoir's shores host the Playa del Tamujoso, a bathing area of slate soils planted with pines and eucalyptus where canoeing and sailing take place. Fishing, swimming, picnics and water sports are among the reservoir's recreational uses, and in autumn the deer rut can be heard in the surrounding Sierra Morena woodland.

The area offers access to walking paths along the shoreline where visitors can fish, swim, or take walks. The best time to visit is during good weather when the paths are dry and water activities are feasible.

Beneath the water surface lie remnants of ancient settlements from the Argaric culture, approximately 4000 years old, providing insight into early habitation of the region. Archaeologists have discovered old stone walls and storage structures there that show how people of that time worked with metal tools.