Kolleru Lake is the largest freshwater lake in Andhra Pradesh. It is located between the Krishna and Godavari delta. The lake is a natural flood-balancing reservoir for the Krishna and the Godavari River. Budameru and Tammileru rivers feed the lake. The catchment area of the lake is two thousand square kilometers and it is connected to the Krishna and Godavari rivers by means of sixty-eight inflowing drains and channels.

The lake serves as a sanctuary and provides shelter to nearly twenty million resident and migratory birds, which include the Grey or spot, billed Pelican. In November 1999 under India`s Wildlife Protection Act, 1972 the lake was recognized as a Wildlife Sanctuary. In November 2002, it was designated as a wetland of international importance under the International Ramsar Convention.

The historical town of Eluru is situated on the border of the lake. The lake is at a distance of fifteen kilometers from Eluru and sixty kilometers from Vijayawada