Lake Undozero Lake Undozero Lake Undozero () is a freshwater lake, located in the west of Plesetsky District of Arkhangelsk Oblast in Russia. It is one of the biggest lakes in Arkhangelsk Oblast and the second biggest one in Plesetsky District. The area of the lake is , and the area of its basin is . Lake Undozero is the source of the Undosha River, which belongs to the river basin the Onega River and thus to the White Sea basin. The lake has a sophisticated shape and contains a number of islands. The source of the Undosha is in the south-western
White Sea–Baltic Canal waterway length is , of which are man-made. The current flows north from Lake Onega to the White Sea, and all navigation marks are set according to it. Once in Lake Onega, ships can exit the southwest shore through the Svir River (and its two locks) to reach Lake Ladoga and then proceed down the Neva River to Saint Petersburg and the Baltic Sea. Alternatively, from Lake Onega river ships can sail eastward into the Volga–Baltic Waterway. The canal begins near Povenets settlement in Povenets bay of Lake Onega. After Povenets there are seven locks close together, forming the "Stairs