The district has an area of 3,678 Sq.km and with coastal line of 68Km. It is bounded on the north by Viluppuram District and Kallakurichi district, on the east by the Bay of Bengal, on the northeast by Puducherry district of the union territory Puducherry, on the south by Mayiladuthurai district, on the west by Perambalur District and by a small part with Thanjavur district. The district is drained by Gadilam and Ponnaiyar rivers in the north, Vellar and Kollidam River (Coleroon) in the south. The district has lignite deposit that helps in production of electricity etc,. The district is also one of the most robust fishing areas in the state of Tamil Nadu, and home to a large number of fisher population. Agriculture and industries are also main profession of this district peoples. Jackfruits and Cashew nuts are also famous in this district. World famous sugar and chocolates are being manufactured in this district.
Cuddalore district has been classified as a multi-hazard prone district, since the district is prone to the natural calamities such as cyclonic depressions and the resultant rains which causing floods. The Cyclone “Nisha” in 2008 and the cyclone “ Thane “ in December 2011 were caused heavy damage to this district.