Don (dŏn, Rus. dôn) [key], river, SW European Russia. It rises SE of Tula and flows c.1,200 mi (1,930 km), first SE past Voronezh, then SW into the Sea of Azov. At its eastern bend the Don is linked by a canal (c.65 mi/105 m long), with the Volga River near Volgograd (formerly Stalingrad). The annual flood of the river is controlled by the Tsimlyansk Reservoir. Rostov-na-Donu is the chief city and port on the Don. Navigable for c.850 mi (1,370 km) and accessible to seagoing vessels as far as Rostov-na-Donu, the Don is an important artery for grain, coal, and lumber shipments. The chief tributary of the Don is the Donets, which connects it with the industrial Donets Basin. Known to the ancients as the Tanaïs, the Don has been a trading channel since Scythian times.