The Tosna () is a northward

river A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of ...

in Luzhsky, Tosnensky, and Kirovsky Districts of

Leningrad Oblast Leningrad Oblast (, ; ; ) is a federal subjects of Russia, federal subject of Russia (an oblast). The oblast has an area of and a population of 2,000,997 (2021 Russian census, 2021 Census); up from 1,716,868 recorded in the 2010 Russian census ...

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

, as well as in the city of

Saint Petersburg Saint Petersburg, formerly known as Petrograd and later Leningrad, is the List of cities and towns in Russia by population, second-largest city in Russia after Moscow. It is situated on the Neva, River Neva, at the head of the Gulf of Finland ...

. It is a left

tributary A tributary, or an ''affluent'', is a stream or river that flows into a larger stream (''main stem'' or ''"parent"''), river, or a lake. A tributary does not flow directly into a sea or ocean. Tributaries, and the main stem river into which they ...

of the

Neva The Neva ( , ; , ) is a river in northwestern Russia flowing from Lake Ladoga through the western part of Leningrad Oblast (historical region of Ingria) to the Neva Bay of the Gulf of Finland. Despite its modest length of , it is the fourth- ...

. The towns of

Tosno Tosno () is a town and the administrative center of Tosnensky District in Leningrad Oblast, Russia, located on the Tosna River, southeast of the center of St. Petersburg. Population: History The village of Tosno was first mentioned in Rus ...

, Nikolskoye, and Otradnoye, as well as the urban-type settlement of Ulyanovka are along it. Its length is . Its

drainage basin A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, ...

covers which mainly has northward flowing streams. Its main tributary is the Yeglinka which is on the

left bank In geography, a bank is the land alongside a body of water. Different structures are referred to as ''banks'' in different fields of geography. In limnology (the study of inland waters), a stream bank or river bank is the terrain alongsid ...

. The source is in swamps south of the settlement of Radofinnikovo. The river flows north, enters Tosnensky District, passes the town of Tosno, and essentially enters the suburbs of

. There, it flows through Ulyanovka and Nikolskoye. In this area,

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

rocks occasionally form the banks. In particular, Sablinskiye Caves, disused quarries, are by the river. A stretch of Tosna between Nikolskoye and Otradnoye serves as a border between the city of Saint Petersburg (west) and Leningrad Oblast (east). The mouth/confluence abuts the west of Otradnoye, a town.

References

Rivers of Leningrad Oblast {{Russia-river-stub