Hogenakkal Falls, Waterfall in Dharmapuri district, Tamil Nadu, India.

Hogenakkal Falls is a cascade in Dharmapuri district, Tamil Nadu, India, where the Kaveri River flows over dark carbonatite rock. The water splits into several parallel streams that shift from narrow trickles to wide curtains depending on the season.

Sangam literature names the falls Thalaineer aruvi and calls the surrounding country Thalaineer Naadu, ruled by Adiyaman Neduman Anji, a king praised in Purananooru, Agananooru and Kurunthogai. The Tamil name Uguneer Kal was recorded as Hogenakkal in Kannada by tax officials of the Mysore rulers, a form kept in British-era revenue records.

The name Hogenakkal comes from Kannada for 'Smoky Rocks', after the spray that rises where the Kaveri hits the rock. Tamil speakers also call the falls Marikottayam, and old Tamil texts use the name Uguneer Kal. Visitors can hire a bamboo coracle, called parisal in Tamil and teppa in Kannada, and have freshly caught fish cooked at stalls on the sand.

Boating with bamboo coracles, called parisal in Tamil and teppa or harigolu in Kannada, runs in the dry season when the current slackens; each coracle holds about eight people. The best time to see the river in full spate is just after the monsoons, while off-season visits are quieter. Summer water temperatures range from 23 to 34 °C, winter from 13 to 27 °C.

The falls cut through two magmatic dykes of pyroxenite interrupted by carbonatite, rock dated to about 1,994 ± 76 million years ago in the Orosirian period. These carbonatites are considered the oldest of their kind in South Asia. The river drops as much as 20 m in places, and the roar is compared to continual thunder.