Wierzyca (also Wierzysza, Werysa, Latin Verissa, Kashbian Wierzësa, German Ferse) - a river in northern Poland, a left tributary of the lower Vistula. The river is 151.4 km long and the river basin area is 1603 km² [3]. Wierzyca flows out of the small Piotrowskie Lake in the Kashubian Lake District near the town of Piotrowo, south-east of Wieżyca. It flows south-east, meandering in places. It is a canoe trail. There are numerous hydroelectric power stations in its course. It flows into the Vistula near the town of Gniew. The name of the Wierzyca river is sometimes confused with the name of several peaks called Wieżyca.