Lake Medesno is located in the Gorodok district of the Vitebsk region, 30 km north-east from the town of Gorodok, about 0.9 km south of the village Zarechye and belongs to the basin of the r. Oatmeal (pr. Tributary. Usvecha), which flows through the lake. The terrain is flat, in some places it is ridge-hilly, densely overgrown with forest, in some places marshy.