Pääjärvi () is a medium-sized lake in Finland. It is situated on the border between the city of Hämeenlinna in the Kanta-Häme region and the municipality of Hollola in the Päijät-Häme region.Pääjärvi in Järviwiki Web Service. Finnish Environment Institute. Retrieved 2014-03-19.
The lake drains through the Teuronjoki river into the 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.
See also List of lakes in Finland
References