Ardhagiri hill is situated in Aragonda village of Chittoor district in the Indian state of Andhra Pradesh. Veeranjaneya temple is on the hill of Ardhagiri, dedicated to Lord Hanuman. The hill of Ardhagiri translates to half mountain, a fallen part of Sanjeevani mountain transported by Lord Hanuman in Tretayuga. Hence, the name Ardhagiri and the temple were dedicated to Lord Hanuman.

When Lord Hanuman found Sanjeevani to save Lakshmana during the war with Ravana, he carried the entire hill as he could not recognize the Sanjeevani plant. It is believed that, a part of the hill (carried by Hanuman) was dropped at this place and called as Ardhagiri (half hill). It is believed that consuming the water of Pushkarini at this temple can get cure a person of all diseases

Many people, even today, come from all across the world to collect the medicated water in the pond, besides to pray at the temple. The clay in the mountain contains many medicinal properties and has a power to cure many types of skin problems. The water in the pond comes from different places from the mountain, touching many roots of medicinal plants.

Source:

Nair, Shantha (2014). Sri Venkateshwara. Jaico Publishing House. ISBN 81-8495-445-X. Retrieved 5 November 2014.

https://en.wikipedia.org/wiki/Ardhagiri

https://en.wikipedia.org/wiki/Veeranjaneya_Temple,_Ardhagiri