In most of the holy places the Deity is found atop the hill. But here the Holy hill itself is the Deity (Lord Annamalaiyar) and is worshipped. "Arunam" means sun and denotes the red colour of fire. "Asalam" means "Giri" or "malai" (mountain). Thus "Arunachalam" means the HOly hill which is rd in colour. The Holy hill is 2668 fi. high.
The Annamalai Hill was Agni (fire) during Kirthayugam, was Manikkam (Emerad) during Threthayugam, was Pon (Gold) during Dwaparayugam and rock during Kaliyugam. There are eight lingams located at the eight directions and provides an octagonal structure to Thiruvannamalai Town. The eight lingams are: Indra Lingam, Agni Lingam, Yama Lingam, Niruthi Lingam, Varuna Lingam, Vayu Lingam, Kubera Lingam and Esanya Lingam. The Adi Annamalai Temple glorified in Dhevaram is located on this path.
The circumambulation path is 14 kilometres. History has it that even today a number of siddhars are living on the hill. It is auspicious to perform "Girilvalam" during every Full moon day which would do immense good. It is because during Full Moon Day siddhars movement would be there and the whole atmosphere would be filled with perfumes of herbal plants. This will provide peace of mind and good health to body. It is a proven fact that on every Full moon day lakhs of devotees circumambulate the Hill and get all benefits by praying to Lord Annamalaiyar.
The circumambulation path has been provided with sodium lamps at the expense of 12 lakhs donated by cine artist Thiru Rajinikanth. This benefits pilgrims who perform circumambulation during night times. On behalf of Town administration bore well pumps are erected to supply drinking water to pilgrims. Moreover for the benefit of the devotees during special occasions annadhanam is performed by Sri Agasthiar Ashram,and so many donors. Milk is distributed by certain well wishers.