Udayagiri Fort, with historical prominence, is about 34 km from Kanyakumari, in Tamil Nadu. It was rebuilt during the reign of Marthanda Varma in 1741-44. In early times, Udayagiri Fort was used by Tipu Sultan to keep the prisoners.

The prime attraction is a 16 ft long brass gun, which could not be removed even with the help of 16 elephants. The tomb of De Lennoy – a trusted General of King Marthanda Varma – is located here. De Lennoy trained soldiers in the European method of fighting. A foundry for casting guns and cannon balls were also established within the fort under the supervision of the General.

The adjoining areas of the fort are home to deer, ducks, birds and over 100 varieties of trees.