Thoothukudi District is one of the 38 districts of Tamil Nadu state in southern India. The district was formed by bifurcation of Tirunelveli district on 20 October 1986. Thoothukudi is the district headquarters and largest city of the district. The district is known for fishing as well as pearl cultivation, with an abundance of pearls being found in the seas offshore. Thoothukudi district has many historical sites such as Adichanallur and the ancient trade port of Korkai.

The Thamirabarani or Tamraparni or Porunai is a perennial river that originates from the Agastyarkoodam peak of Pothigai hills of the Western Ghats, above Papanasam in the Ambasamudram taluk. It flows through Tirunelveli and Thoothukudi districts of the Tamil Nadu state of southern India into the Gulf of Mannar. It was called the Tamraparni River in the pre-classical period, a name it lent to the island of Sri Lanka. The old Tamil name of the river is Porunai. From the source to sea, the river is about 128 kilometres (80 mi) long and is the only perennial river in Tamil Nadu. This river flows towards north direction initially. However, it changes to east direction later.