The Noyyal River rises from the Vellingiri hills in the Western Ghats in Tamil Nadu, southeastern India and drains into the Kaveri River. The river's basin is 180 km (110 mi) long and 25 km (16 mi) wide and covers a total area of 3,500 km2 (1,400 sq mi). Cultivated land in the basin amounts to 1,800 km2 (690 sq mi) while the population density is 120 people per km² (311/mi²) in the countryside, and 1000 people per km² (2590/mi²) in the cities.