Chidambaram is a town and municipality in Cuddalore district in the Indian state of Tamil Nadu, on the banks of the Vellar River where it meets the Bay of Bengal. It is the headquarters of the Chidambaram taluk. The town is believed to be of significant antiquity and has been ruled, at different times, by the Pallavas until ninth century, Medieval Cholas, Later Cholas, Later Pandyas, Vijayanagara Empire, Thanjavur Nayakas, Marathas and the British. The town is known for the Thillai Nataraja Temple and Thillai Kali Temple, and the annual chariot festival held in the months of December–January (In the Tamil month of Marghazhi known as "Margazhi Urchavam") and June to July (In the Tamil month of Aani known as "Aani Thirumanjanam"). One of the Divya Desams Divya Sri Govindaraja Perumal Temple (Thiruchitrakoodam) is a part of Thillai Nataraja Temple complex. Thiruvetkalam Shiva Temple, Vadakiruppu, Thirunelvayil Shiva Temple, Sivapuri and Tirukkazhippalai Palvannanathar Temple are the other three ancient Shiva temples in the region.
Chidambaram covers an area of and had a population of 62,153 as of 2011. It is administered by a Selective grade municipality. Tertiary sector involving tourism is the major occupation. Roadways are the major means of transportation with a total of of district roads including one national highway passing through the town. As of 2011, there were eleven government schools: six primary schools, three middle schools and two higher secondary schools in Chidambaram. Annamalai University, established in 1929 in Chidambaram, is one of the oldest and most prominent universities in the state.
Chidambaram is one of the many temple towns in the state which is named after the groves, clusters or forests dominated by a particular variety of a tree or shrub and the same variety of tree or shrub sheltering the presiding deity. The traditional name of the temple complex, Chidambaram Thillai Nataraja-koothan Kovil. The mangrove forests of Thillai trees (Excoecaria agallocha) were abundant in the town once.