Ilanji is a village located in Tirunelveli district of the southern state of India, Tamil Nadu. The panchayat looks after the local administration of the place. The towns of Sen Kottai, Courtallam and Tenkasi are geographically placed in such a way that they form a triangle. Ilanji occupies the center of the triangle and is approximately 3 km from each of these towns. Therefore it is also known as the triplet city in Tirunelveli district. Two great rivers Therkaru and Vadakkaru surround the town. The nearest access point is the Tenkasi Junction Railway Station.

The India census report published in 2001 states that Ilanji had a population of 9423. Males account for 515 of the population and females comprises of 49% of the population. In Ilanji, 10% of the population is less than six years of age. The literacy rate of this panchayat town as revealed in the census report is 66%. This is a progressive trend because the national average literacy rate is 59.5%. Out of it, the male literacy rate is 75% and the female literacy rate is 57%.

Kumarar Koil, a temple dedicated to Lord Murugan is the prime attraction of this village. The temple is located amongst dense trees and lush green fields. The village is embellished with many other temples, which are Keela Kovil, Pillayar Koil, Perumal Koil and Sitrattu Veeramman Kovil also known as Sithai Amman Koil.