Vselug is a lake in the Tver region of Russia, on the Valdai Upland. The area (together with Lake Peno) is 37 km², the length is 14 km, the width is up to 4 km. The average depth is 7.7 m, the largest - 16 m.
Via Vselug passes the upper course of the Volga River after leaving the Lake Sterzh. The lake is a ples (an extension of the river). The coast is flat, along the coast stretches a shallow width of 15-20 m, composed of pebbles and boulders.
It is regulated by the Upper Volga Beyslot.
Developed fisheries. Earlier the lake was navigable, along it passed the passenger line Peno - Shirkov Pogost - Kokovkino with a length of 60 km, served by the ship "Zarnitsa".