It is one of the biggest and most important lakes of our country, and the biggest in Thrace. It is 45.000 acres and is situated between the prefectures of Rodopi and Xanthi, and administratively it belongs to both. Despite its size, it is a shallow lake since the deepest point is no more than 4m. In Vistonida three lakes flow into it; Kosinthos, Kompsatos and Travos. This has as a result, the river water which these rivers provide, to be mixed with the salty water which is coming from the sea through three canals.
The Lake Vistonida, which according to mythology was home to the Thracian tribe of Viotones, is habitat to many flora species and also many birds and animals. More than 300 bird species have been observed and the area is famous for the unique Heron habitat, which has been created across Porto Lagos. The fauna is completed by the wild mammals. In the area near the lake you can see rich vegetation of populous, platanus, willows and elms which grow due to the area and the climate. Also the lake is full of fish which enter it from the sea. A usual catch includes eels, Mediterranean sand smelts, gilt-head breams, sea bass as well as the local fish, likurinos.
There is an information point about the lake near Porto Lagos where you can get relevant information. Bird watching is also developed in the area. Vistonida Lake with the Nestos Delta has been included in the Ramsar Convention, and in the European Network (NATURA) 2000 as special protection areas.