Lake Szadzko is shaped like a marrow. It is 2 km long and 500 wide in its widest point. The lake, fed by a stream named Pęzinka, is very shallow, with only 1-2 m depth. First reed and then trees have grown on the sand deposits carried by the Pęzinka, forming a peninsula oriented towards the village of Szadzko, known among the locals as the Long Neck (Długa Szyja) or the Long Throat (Długie Gardło).