hidden Tosna River, the TOSNA, river, left-hand tributary of the Neva. It flows in Luga, Tosno, and Kirovsk Districts of Leningrad Oblast and in St. Petersburg. Length: 121 km. Catchment area: 1640 sq. km. Flow rate: 11.6 cu. m/s. The source is in Luga District, 5 km... more