Hogenakkal Falls or Hogenakal Falls is a waterfall in South India on the river Kaveri. It is located in the Dharmapuri district of the southern Indian state of Tamil Nadu, about 180 km (110 mi) from Bangalore and 46 km (29 mi) from Dharmapuri town. It is sometimes referred to as the "Niagara of India". With its fame for medicinal baths and hide boat rides, it is a major site of tourist attraction. Carbonatite rocks in this site are considered to be the oldest of its kind in South Asia and one of the oldest in the world. This is also the site of a proposed project to generate drinking water.
The word Hogenakal is formed of two Kannada words hoge and kal. When the water falls on the rocks it appears as if hoge (smoke) is emanating from the top of the kal (rock) because of the force of the water, hence Hogenakkal (smoking rocks). It is also called as Marikottayam by the people of Tamil Nadu.
The Kaveri is considered to form at Talakaveri in the Brahmagiri hills in the Western Ghats of south India and gathers momentum as the land drops in elevation. It becomes larger as various tributaries feed into it on the way down. At Hogenakkal, the Kaveri, now a large river, drops and creates numerous waterfalls as the water cuts through the rocky terrain. In places the water falls as much as 20 m (66 ft) and is said to sound like continual thunder. Soon after the falls the river takes a southerly course and enters the Mettur Stanley Reservoir. The river carries sediment which makes the downriver land fertile.
At Hogenakkal the river spreads out over a wide area of sandy beaches, then flows through to the Mettur Dam and creates a 60 sq mi (160 km2). lake called Stanley Reservoir. Built in 1934, this project improved irrigation and provided hydropower.