At a distance of 1 km from Kumbakonam Railway Station, Mahamaham Tank is a huge temple tank located in the heart of Kumbakonam town in Tamil Nadu. It is considered to be the foremost and one of the largest temple tanks in Tamil Nadu.
The tank covers an area of 6.2 acres and is trapezoidal in shape. The tank is surrounded by 16 small Mandapams (shrines) and has 21 wells inside the tank. Govinda Dikshitar, the chieftain of Ragunatha Nayak of Thanjavur, constructed the sixteen Mandapams and stone steps around this tank. Brahmatheerthesar, Mukunthar, Thalesar, Rishakesar, Umaipakesar, Nairuthesar, Brahmeesar, Gangatheerthesar and Seshtra Paleesar, are the names of deities located in these Mandapams.
There are 21 wells inside the tank in the shape of small spring wells. Beginning the eastern side of the tank, there are 8 wells in the name of celestial deities namely Indra, Yama, Agni, Niruthi, Vayuya, Kubera and Isanya respectively. In between the Vayu and Kubera wells, the ninth well is located called Brahma Theertham. Commencing from the north of Vayu Theertham, there are nine wells indicating the holy rivers of India, namely the Ganges, Yamuna, Godavari, Narmada, Saraswathi, Kaveri, Tungabhadra, Krishna and Sarayu.
Masimaham is an annual event that occurs in the Tamil month of Masi (February-March) in the star of Magam. Once in twelve years, when the planet Guru (Jupiter) enters Simha (Leo) sign, the Kumbh mela festival is celebrated at Mahamaham tank. 12 Shiva temples and 5 Vishnu temples are connected with this festival. They are Kasi Viswanathar Temple, Kumbeswarar Temple, Nageswara Temple, Someswarar Temple, Koteeswarar Temple, Kalahasteeswarar Temple, Gowthameswarar Temple, Amirthakalasanathar Temple, Banapuriswarar Temple, Abimukeswarar Temple, Kambatta Visvanathar Temple and Ekambareswarar Temple. Of them 10 temples are in Kumbakonam. The Vishnu temples are Sarangapani Temple, Chakrapani Temple, Ramaswamy Temple, Rajagopalaswamy Temple, and Varahaperumal Temple. The processional deities of these temples come to this tank during festival days and at noon, all the deities bathe along with the devotees - it is called Theerthavari. The temple cars of major temples in Kumbakonam come around the city on the festival night.
During the time of Mahamaham festival, it is also believed that taking bath in the holy stream of water from the famous rivers are mixed together in Mahamaham tank, would get rid of sins according to Hindu religion. During this festival, thousands of Hindu devotees come to Kumbakonam and take bath in Mahamaham tank.