| Pääjärvi | |
|---|---|
| Location | Hämeenlinna, Hämeenkoski |
| Basin countries | Finland |
| Surface elevation | 102,9 m |
Pääjärvi is a lake in Finland. It is situated on the border between the city of Hämeenlinna (in the area of the former municipality of Lammi) in the Tavastia Proper region and the municipality of Hämeenkoski in the Päijänne Tavastia 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 and it is thus a part of the Kokemäenjoki basin that drains the western third of the Finnish Lakeland.
In Finland there are several lakes with the name Pääjärvi and Pääjärvi is also the Finnish name for Lake Pyaozero in the Republic of Karelia in Russia.