Onega River traditionally explained as related to Finnish "Enojoki" - the main river, stream. In terms of both area of the basin and the average discharge, the Onega is the third river basin of the White Sea (behind the Northern Dvina and the Mezen. The river basin of the Onega is spread over the west of Arkhangelsk Oblast, north-west of Vologda Oblast, and also includes minor areas in the east of Republic of Karelia. The Onega basin includes some of the biggest lakes of Arkhangelsk and Vologda Oblasts, such as Lake Vozhe, Lake Lacha, Lake Lyokshmozero, Lake Kenozero, Lake Undozero, and Lake
Arkhangelsk Oblast and the non-freezing harbour of Murmansk, lost its significance as the main trading harbour of the Russian Empire. However, in the early 20th century Arkhangelsk was an important starting point for Russian Arctic expeditions. For instance, in the 1830s Pyotr Pakhtusov sailed twice from Arkhangelsk to investigate and map Novaya Zemlya. In 1932 the "Icebreaker Sibiryakov" under the command of Vladimir Voronin, sailing from Arkhangelsk, crossed the Northern Sea Route in a single navigation. In 1918 and 1919, Arkhangelsk Governorate became one of the most active battlegrounds of the Civil War in Russia. On August 2, 1918, Arkhangelsk was occupied