Nagapattinam district is one of the 38 districts (a coastal district) of Tamil Nadu state in southern India. Nagapattinam district was carved out by bifurcating the erstwhile composite Thanjavur district on 19 October 1991. The town of Nagapattinam is the district headquarters. As of 2011, the district had a population of 697,069 with a sex-ratio of 1,025 females for every 1,000 males. Until Mayiladuthurai district was created out of it on 24 March 2020, Nagapattinam was the only discontiguous district in Tamil Nadu.