It is believed that Thirunelli was once an important pilgrim center of the Hindus given its location. The temple is built in a valley that is surrounded by mountains on all four sides. The forests surrounding the temple are thick and extremely dense making it quite a task to access the temple.
There are no records to show when the temple was built though it is thought to be very ancient. Records show that the temple was in existence between 962-1019 CE. Even then the temple was an important place of worship for the South Indians. Archeologists have found ruins of at least two villages near to the temple.
Looking at the temple, one can only marvel that the structure still stands after all these centuries.