Osmankajärvi is a medium-sized lake in the Oulujoki main catchment area. It is located in the region Kainuu in Finland. List of lakes in Finland Osmankajärvi...

Onkamojärvi, Onkivesi, Ontojärvi – Nurmesjärvi, Orajärvi, Orivesi, Osmankajärvi, Otermanjärvi, Oulujärvi Pääjärvi (1), Pääjärvi (2), Paatari (Paadaar)...