Thirunageswaram is one of the 127 temples on the southern banks of river Cauvery. It is one of the Panchakrosa Sthalas. The presiding Deity is Arulmigu Giri Gujambika Sametha Naganathaswamy. The Raaghu Sannathi ( Nagaraja Shrine)is on the South-West direction of the second prakara.Raaghu, the Naga (Serpent) King worshipped the Lord Siva. Hence this place was named as ‘Thirunageshwaram'. Rahu had received a boon from Siva for bestowing grace and prosperity to those who worship him with devotion. He took His abode as God with His two consorts. There is another shrine for Amman, where Devi is seen in three forms as Lakshmi(godess of wealth), Girigujaambaal (sakthi) and Saraswathi (godess of knowledge). As per the Sthalapuranam, there are two Shrines (Sannidhis) for the Presiding Deity (Moorthi) at this sthala, the colour of milk changes from white to blue during Abhishekam. On 16.2.86, a snake had shed off its outer skin on Rahu Bhagavan, which is preserved and worshipped to date. People having Rahu dosha come here during Rahu kalam and perform Abishekas. The Jothisha Sastra (Astrololgy) states that if Raaghu is in good position in one's horoscope. He will bestow all prosperity (including Raja Yoga ) to him and that person becomes a Kubera. If he is not in a good position and guilty ( Dhosha ) a person gets worst results and his life will be miserable. Therefore one should satisfy Raaghu (one of the 9 planets) by worshipping Him. One's marriage will be delayed if Rahu is in the 7 th place in a horoscope. If he is in the 5 th place, the Jaathaka (person) will not beget a child. In order to nullify Kalasthra dhosha, Naga dhosa and Putra dhosha one should worship Raaghu. People afflicted with Nagadhosa should perform oblations.

Rahu is God of the Ascending / North lunar node. Rahu may be shown riding a black lion or as seated on a Sirhhasana (throne) or in a silver chariot drawn by eight horses. He may have two hands, the right hand carrying a woollen blanket and a book, the left hand being shown empty. If four hands are shown, they can carry sword, shield and lance, the fourth one being in Varada-mudra. According to legend, during the Samudra manthan, the asura Rahu drank some of the divine nectar. But before the nectar could pass his throat, Mohini (the female avatar of Vishnu) cut off his head. The head, however, remained immortal and is called Rahu, while the rest of the body became Ketu. It is believed that this immortal head occasionally swallows the sun or the moon, causing eclipses. Then, the sun or moon passes through the opening at the neck, ending the eclipse. In Hindu mythology, Lord Rahu is described as the head of a demonic snake that swallows the sun and moon, causing eclipses. Rahu is a shadowy planet and do not have any special day dedicated to him. He is depicted in art as a dragon with no body riding on a chariot drawn by eight black horses. When Rahu is affected one faces several miseries and obstacles in the way of success. The gemstone of Rahu is Gomedh or Honey Colored Hessonite.

Thirunageswaram is located 6 km from Kumbakonam on Karaikal road. Nearest Railway station is at 2 k.m far at Theprumanallur (Thirunageswaram). Oppiliappan kovil is the nearest temple.