The Nallamalas are a section of the Eastern Ghats which stretch primarily over Kurnool, Guntur, Prakasam, Kadapa and Chittoor districts of the state of Andhra Pradesh and Mahabubnagar,Nalgonda districts of the state of Telangana India. They run in a nearly north-south alignment, parallel to the Coromandel Coast for close to 430 km between the rivers, Krishna and Pennar. Its northern boundaries are marked by the flat Palnadu basin while in the south it merges with the Tirupati hills. An extremely old system, the hills have been extensively weathered and eroded over the years. The average elevation is about 520m which rises to 1100 m at Bharani konda and 1048 from Gundia Brahmeswara .Both these peaks are at the northwest direction from the town of Cumbum. There are many peaks above 800m.
These hills are thickly forested and remain largely unexplored and are inhabited by hostile tribes. The famous Nagarjuna Sagar, Srisailam Tiger Reserve is situated here. Srisailam on the river Krishna is the site of a large hydroelectric project and is also known for an ancient temple of Lord Shiva.
The Bhramaramba Mallikharjuna swamy temple is an ancient and holy temple of Srisailam. It holds great historical and religious significance. This temple is situated on the 457-meter high hill located on the south bank of the river Krishna, in the Nallamala forest. This temple is regarded as one of the twelve Jyothirlingas in the country. The temple is also called as “Sri Mallikharjunam” and “Sri Parvatham”. Goddess Maha kali is also seated here in the form of Bhramaramba, she is also the consort of Lord Mallikharjuna. This sacred temple is open for people belonging to all caste and creed, who can worship and even touch the deity.
The Mahanandi temple and the Ahobilam Nava Narasimha temple are also found in these hills. A streams flows down the Gundla Brahmsehwara peak and culminates in a beautiful water fall and the sacred pond called Namaligundam (peacock pool).
The Mallela Theertham on the river is located in the forest .The Cumbum lake is one of the Asia’s oldest manmade lakes and dates back to the 15 century AD. It was built by the Gajapati kings of Odisha for the purpose of irrigating 420km2of farm land .It was repaired by the queen Varadharajamma of the Vijayanagar dynastery in the 16th century AD.
Source: http://www.indianaturewatch.net/displayimage.php?id=377365