Situated around 70 kms from Nagapattinam, this sanctuary was created in 1967 for the conservation of Blackbucks. Its sandy coast is fringed by saline swamps and thorny scrub. It is known for the congregation of waterbirds, especially the great flamingos.
The sanctuary has high biodiversity with many unique species of animals and birds. The Bottlenose Dolphin is frequently seen along the shore which is also a nesting site for olive ridley turtles. There are around 103 species of water birds and their numbers are believed to have a peak population of 100,000. Over 364 flowering plant species have been identified in the sanctuary of which 198 have medicinal properties.