Kanyakumari district (Tamil: [kɐnːijaːkumaːɾi]), officially Kanniyakumari district, is one of the 38 districts of Tamil Nadu state and the southernmost district in mainland India. It stands second in terms of population density among the districts of Tamil Nadu. It is also the richest district in Tamil Nadu in terms of per capita income, and also tops the state in Human Development Index (HDI), literacy, and education. The district's headquarters is Nagercoil.
Kanyakumari district has a varied topography, with the sea on three sides and the mountains of the Western Ghats bordering the northern side. Except for a small stretch of land to the east of Kanyakumari town, almost the entire district is sandwiched between the Western Ghats and the Arabian Sea – the only district in Tamil Nadu state facing the Arabian Sea.