Krishna Raja Sagara, Water reservoir in Karnataka, India.

Krishna Raja Sagara is a water reservoir on the Kaveri River in Karnataka state, roughly 12 kilometers northwest of Mysore. The body of water extends over several kilometers and is held back by a dam that regulates the river flow.

Construction began in 1911 under Krishna Raja Wadiyar IV, who sanctioned the scheme after Sir M. Visvesvaraya's design, and the dam was completed in 1932. Disputes with the Madras Presidency over Kaveri water were settled by the 1924 agreement, allowing work to resume. The reservoir submerged 25 villages and displaced about 15,000 people.

The name honours Krishna Raja Wadiyar IV, who sanctioned the scheme after Sir M. Visvesvaraya threatened to leave Mysore service. Local lore derives Kannambadi, the village the reservoir submerged, from the sage Kanva, who is said to have performed penance on the Kaveri bank there.

The dam lies about 12 miles from Mysore and 9 miles from Srirangapatna, near Kannambadi. A 14.5-foot-wide road runs along the top of the wall, and the adjoining Brindavan Gardens hold a musical fountain and a rest house for visitors.

The dam uses automatic gates that regulate water levels without manual intervention. This system makes managing large volumes of water during the rainy season easier.