The Western Dvina is a river flowing in the western part of the East European Plain. The river flows through the territory of three countries: Russia, Belarus and Latvia. The length is 1020 km, the basin area is 87.9 thousand km2. It originates in the Valdai Upland, and then flows through Lake Okhvat (a series of large stretches connected by channels) and flows into the Gulf of Riga of the Baltic Sea, forming a delta.