Mahamaham tank is a huge temple tank located in Kumbakonam, Tamil Nadu, India. It is considered to be the foremost and one of the largest temple tanks in Tamil Nadu. The Masimaham festival held in the tank has 100,000 visitors and the once-in-12-year Mahamaham festival has close to 2 million visitors.

Kumbakonam, or Kudanthai, is a city municipal corporation in the Thanjavur district in the Indian state of Tamil Nadu. It is located 40 km (25 mi) from Thanjavur and 282 km (175 mi) from Chennai and is the headquarters of the Kumbakonam taluk of Thanjavur district. It is the second largest city in the district after Thanjavur. The city is bounded by two rivers, the Kaveri River to the north and Arasalar River to the south. Kumbakonam is known as a "Temple town" due to the prevalence of a number of temples here and is noted for its Mahamaham festival, which happens once in 12 years, attracting people from all over the country.