a reservoir built in 1958 on the Oskol River (Severskii Donets Basin) in Kharkov Oblast and part of Donetsk Oblast, Ukrainian SSR. Area, 130 sq km; volume, 0.48 cu km; length, 125 km; maximum width, 4 km; average depth, 4 m. It is fed primarily by snow.
The Krasnooskol Reservoir has made long-term regulation of the water flow possible. It was created as part of the Severskii Donets-Donbas canal system, to be used for water supply, irrigation, and power engineering. There is fishing for pike, bream, pike-perch, wild carp, and sheatfish.