This lake is also known as the Chilika Lake and it is the largest coastal lake in India. The area of the lake varies from 1165 square kms in the monsoon season to 906 square km in the dry season, and is studded with numerous small islands and is the largest brackish water lake in the country. This lake attracts a large number of migratory birds besides the resident ones. Barkul and Rambha are two places on the lake, which serve as the base.

Though the lake can be visited throughout the year, October to March is the best season. This brackish water coastal lake was formed in the south of the mouth of the Mahanadi river and was formed due to the silting action of the Mahanadi river, which drains into the northern end of the lake and the northerly currents in the Bay of Bengal, which have formed a sandbar along the eastern shore leading to the formation of a shallow lagoon.

The lake is an important habitat and breeding ground for both resident and migratory and aquatic birds, most notably flamingos. Migratory birds arrive in October from as far away as Siberia, Iran, Iraq, Afghanistan and the Himalaya, and generally stay until March. Part of the lake is protected by the Chilka Lake Bird Sanctuary, which harbors over 150 migratory and resident species of birds. The Nalaban Island within the lagoon is classified as a Bird Sanctuary under the wildlife protection act.

The lake is also home to a diverse range of aquatic life, including 225 species of fish. Chilka Lake is designated a wetland of international importance under the Ramsar Convention, since over a million migratory waterfowl and shorebirds winter here and many vertebrate species have been recorded here. As an estuarine lagoon, it supports a unique assemblage of marine, brackish and freshwater species and, since several rare and endangered species are found in the region.