Sajno Lake - with an area of 522,5 ha, is the largest lake in the group of Augustów lakes. On the east, Sajno is connected by an isthmus with Sajenek Lake and further with a smaller lake, Sajenek Pond. The Bystry Canal has an outlet in the northern part of the lake, and it connects the lake with Augustów. The maximum depth is 27m. The name of the lake probably derives from the Yotvingian word: soia, meaning the river or the river waters (a strong current runs through the centre of the lake). The lake is a quiet zone.
