Pątnowskie Lake is a lake in central Poland known as Jezioro Pątnowskie in Polish. It is located in Konin County in Gmina Ślesin, near the town of Licheń Stary. It is a post-glacial ribbon lake with a weakly developed shoreline. To the north it is connected to Ślesińskie Lake and Mikorzyńskie Lake and forms part of the 32-kilometer navigable Ślesińskie Canal.