a river in Vologda Oblast, RSFSR; a left tributary of the Severnaia Dvina. The Sukhona measures 558 km in length and drains an area of 50,300 sq km. It originates in Lake Kubenskoe, the drainage of which is regulated by a dam with a navigable sluice. In the upper course the floodplain is broad. In the spring, the head of the Vologda and Lezha rivers causes a slight change in gradient, and, as a result, the current of the Sukhona is reversed into Lake Kubenskoe. In the middle course the valley reaches 80–100 m in depth, and the channel abounds with rifts; there are also rapids and rocky islands. In the lower course the velocity of the current is low.
The Sukhona is fed primarily by snow. High water lasts from April to mid-July. The mean flow rate 39 km from the mouth is 456 cu m per sec; the maximum flow rate is 6,520 cu m per sec, and the minimum is 17.6 cu m per sec. The Sukhona freezes between late October and November (in the middle course, as late as December), and the ice breaks up in the second half of April or the first half of May. The river is linked by the Severnaia Dvina Waterway System, via the Sheksna River, with the Volga. It is navigable except in winter and for periods in summer because of low water. The river is also used for floating timber. The cities of Sokol, Tot’ma, and Velikii Ustiug are situated on the Sukhona. The river attracts tourists.