Lake Nero is a shallow, highly eutrophic lake in Yaroslavl Oblast

Yaroslavl Oblast

Yaroslavl Oblast is a federal subject of Russia , which is located in the Central Federal District, surrounded by Tver, Moscow, Ivanovo, Vladimir, Kostroma, and Vologda Oblasts. This geographic location affords the oblast the advantages of proximity to Moscow and St. Petersburg...

, Russia

Russia

Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

. The lake has an area of 54.4 km², a maximum length of 13 km, width 8 km and depth 3.6 m. The bottom of the lake is covered with thick layer of silt

Silt

Silt is granular material of a size somewhere between sand and clay whose mineral origin is quartz and feldspar. Silt may occur as a soil or as suspended sediment in a surface water body...

 sapropel

Sapropel

Sapropel is a term used in marine geology to describe dark-coloured sediments that are rich in organic matter...

 (a sort of ooze used as fertilizer

Fertilizer

Fertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...

 and for other purposes).

The lake is estimated to be about 500 thousand years old, making it one of a few pre-ice age

Ice age

An ice age or, more precisely, glacial age, is a generic geological period of long-term reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental ice sheets, polar ice sheets and alpine glaciers...

 lakes in central Russia.

The first people settled at the lake at 6 thousand years ago. It is historically certain that the Merya tribe had their capital in Sarskoe Gorodishche on the southern shore of the lake. They named the lake Nero (meaning "silty", "marshland") or Kaovo ("place where gull

Gull

Gulls are birds in the family Laridae. They are most closely related to the terns and only distantly related to auks, skimmers, and more distantly to the waders...

s live").

In the 9th Century ast Slavs came to the lake. They called the lake Rostovian Lake in the honor of town Rostov

Rostov

Rostov is a town in Yaroslavl Oblast, Russia, one of the oldest in the country and a tourist center of the Golden Ring. It is located on the shores of Lake Nero, northeast of Moscow. Population:...

.

There are two islands in Nero: Levsky and Rozhdestvenskij . The latter is also known as Gorodskoj. This island formed a pre-ice age

Ice age

An ice age or, more precisely, glacial age, is a generic geological period of long-term reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental ice sheets, polar ice sheets and alpine glaciers...

 monolith

Monolith

A monolith is a geological feature such as a mountain, consisting of a single massive stone or rock, or a single piece of rock placed as, or within, a monument...

.
Flowing into Nero Lake are eight rivers (Sara , Ishnya , Kuchibosh , Mazikha , Varus , Chucherka , Unitsa , Sula etc.), one flows out (Veksa ).

Near Nero Lake is located the town of Rostov

Rostov

Rostov is a town in Yaroslavl Oblast, Russia, one of the oldest in the country and a tourist center of the Golden Ring. It is located on the shores of Lake Nero, northeast of Moscow. Population:...

(on the western shore of the lake) and a few villages (on perimeter): Porech’e-Rybnoe , Ugodichi , Vorzha , L’vy etc.

The first steamboat Emel’yan appeared on the Lake in 1883.