Pääjärvi is a lake in Finland

Finland

Finland , officially the Republic of Finland, is a Nordic country situated in the Fennoscandian region of Northern Europe. It is bordered by Sweden in the west, Norway in the north and Russia in the east, while Estonia lies to its south across the Gulf of Finland.Around 5.4 million people reside...

. It is situated on the border between the city of Hämeenlinna

Hämeenlinna

Hämeenlinna is a city and municipality of about inhabitants in the heart of the historical province of Häme in the south of Finland and is the birthplace of composer Jean Sibelius. Today, it belongs to the region of Tavastia Proper, and until 2010 it was the residence city for the Governor of the...

 (in the area of the former municipality of Lammi

Lammi

Lammi is a former municipality of Finland. It was consolidated with Hämeenlinna on 2009-01-01.It is located in the province of Southern Finland and is part of the Tavastia Proper region. The municipality had a population of 5,507 and covered an area of 611.24 km² of which 73.69 km² is water. The...

) in the Tavastia Proper

Tavastia Proper

Tavastia Proper is a region of Finland. It borders to the regions Finland Proper, Pirkanmaa, Päijänne Tavastia, and Uusimaa.Hämeenlinna is the largest urban area in the region...

 region and the municipality of Hämeenkoski

Hämeenkoski

Hämeenkoski is a municipality of Finland.It is located in the province of Southern Finland and is part of the Päijänne Tavastia region. The municipality has a population of and covers an area of ofwhich...

 in the Päijänne Tavastia

Päijänne Tavastia

Päijänne Tavastia is a region in Southern Finland south of the lake Päijänne. It borders the regions Uusimaa, Tavastia Proper, Pirkanmaa, Central Finland, Southern Savonia and Kymenlaakso.- Historical provinces :...

 region.

The lake drains through the Teuronjoki River into Lake Mommilanjärvi and from there through the Puujoki River into Lake Kernaalanjärvi and from there through the Hiidenjoki River into Lake Vanajavesi

Vanajavesi

Vanajavesi is a lake in Finland. It is part of the Kokemäenjoki basin. The lake gathers waters from a wide area in the regions of Pirkanmaa, Tavastia Proper and parts of the Päijänne Tavastia region.-Settlements:...

 and it is thus a part of the Kokemäenjoki

Kokemäenjoki

The Kokemäenjoki is a river and its drainage basin in southwestern Finland.-Geography:The river originates at Lake Liekovesi in the Pirkanmaa region, and flows to the Gulf of Bothnia at Pori in the Satakunta region...

 basin that drains the western third of the Finnish Lakeland

Finnish Lakeland

Finnish Lakeland or Finnish lake district is the largest of the four landscape regions into which the geography of Finland is divided.The hilly, forest-covered landscape of the lake plateau is dominated by drumlins and by long sinuous eskers...

.

In Finland there are several lakes with the name Pääjärvi and Pääjärvi is also the Finnish name for Lake Pyaozero

Lake Pyaozero

Lake Pyaozero is a large freshwater lake in the Republic of Karelia, northwestern part of Russia. It is located at and has an area of 659 km². There are many islands on the lake with total area of 186 km²...

 in the Republic of Karelia

Republic of Karelia

The Republic of Karelia is a federal subject of Russia .-Geography:The republic is located in the northwestern part of Russia, taking intervening position between the basins of White and Baltic seas...

in Russia.