The Mayar River^[1] is one of the tributaries of the Bhavani in Tamil Nadu, South India. The Mayar river originates from a small town called Mayar off the Masinagudi–Ooty road. This is a natural line of separation between the state of Karnataka and Tamil Nadu and a separation between the forest of Bandipur National Park and the Mudumalai sanctuary to the south.^[2] The Mayar River Gorge is 20 kilometres (12 mi) long and is also called the Mayar Canyon. The river flows into the gorge below Theppakadu in a roaring waterfall called Mayar Falls.^[3] This river is checked by Bhavanisagar Dam on the plains near Satyamangalam, along with the Bhavani River.^{[citation needed]}