South Arcot is a former district of India, located in the state of Tamil Nadu.
South Arcot was the southern portion of the Mughal province (subah) of Arcot. Arcot came under the control of a local Nawab after Mughals lost control southern India in the 18th century. The subah of Arcot was ceded to the British East India Company in 1801, and subsequently the district was split into North Arcot and South Arcot. On September 30, 1993, South Arcot District was split into Cuddalore District and Villupuram District.