Larger part of the lake lies behind the Russian border. The border was drawn after the ratification of Russian-Latvian agreement in 2003. The border can become an unwanted complication to pleasure boats and fishermen ships. If they accidentally cross the border because of bad weather or any other reason, the frontier guards can fine them. The lake is — thanks to its location — sometimes used by especially cigarette smugglers.
Lake Vistytis is of a glacier origin. Its maximum depth reaches 54 meters. Twelve rivers mouth into the lake and only one river flows out of it. The river is called Pissa. A Latvian town Vištytis is situated on the northern bank of the lake.
Lake Vistytis and its closest surroundings are a place of a great nature treasure. A large amount of fauna and flora species had become a reason of its protection. The Russian part was claimed a nature sanctuary in 1975. This national nature preserve is an area of around 335 km². The Latvian part claimed its part a park called Vištyčio regioninis parkas in 1992. The environment of the lake is created by forested mildly sloped hills.