Kadayanallur is a Municipality in Tenkasi district, Tamil Nadu, India. Kadayanallur is approximately 16 km from the town of Tenkasi, the district headquarters. With an area of 52 square kilometres and a population of 90,364, Kadayanallur is classified as a First Grade Municipality under Tamil Nadu's municipal code. Kadayanallur(KDNL) is the biggest as well as largest city in tenkasi district (TSI).