The Cauvery River leaves the Kodagu hills and flows onto the Deccan plateau, forming two islands, Srirangapatna and Shivanasamudra. The river rises at Talakaveri in the Brahmagiri hills in Kodagu. Although there is not a flow at this point all year round, it forms the principal drainage of this district, and is already a major river when it leaves the Western Ghats near Kushalanagara.

After forming two islands, namely Srirangapatna and Shivanasamudra, the river drops into the Hogenakal Falls just before it arrives in the towns of Hogenakal and Srirangam in Tamil Nadu. At Sivasamudra Island the river drops 320 ft (98 m), thus forming the famous Sivasamudram Falls known separately as Gagana Chukki and Bhara Chukki. Asia`s first hydroelectric plant (built in 1902) was on the left falls and supplied power to the city of Bangalore. In 1906, Bangalore became the first city in Asia to be fully electrified and to have electric streetlights, mainly due to the contributions of the islands of the Cauvery River.

In the course of River Cauvery through Karnataka, the channel is interrupted by twelve "anicuts" (dams) for the purpose of irrigation. From the anicut at Madadkatte, an artificial channel is diverted at a distance of 72 miles (116 km), thus irrigating an area of 10,000 acres (40 km²), and ultimately bringing its water supply to the town of Mandya. Near one of the islands of the Cauvery River, Srirangapatna, there is an aqueduct, the Bangara Doddi Nala, which was constructed in the 17th century by the Wodeyar maharaja of Mysore, Ranadhira Kantirava, in reminiscence of his favorite spouse. It is said to be the only channel where the water from a river, was collected upstream and is carried by the aqueduct over the very same river few miles downstream. This aqueduct also served as a motorable bridge between the islands of the Cauvery River until 1964.

The Cauveri River runs through Erode district where river Bhavani converges with it. While passing through Erode, two more tributaries merge. Noyyal and Amaravathi join it before it reaches Tiruchirapalli district. Here the river becomes wide, with a sandy bed, and flows in an easterly direction until it divides into two at upper channel about 14 kilometers west of Thiruchirappalli. The northern branch of river called the Coleroon or Kollidam while the southern branch retains the name Kaveri and then goes directly eastwards into Thanjavur District. These two rivers join again and form one of the Islands of the Cauvery River, namely the Srirangam Island near Tiruchirapalli. The Islands of the Cauvery River are not only scenic pieces of land but also major tourist spots in its own regard.