Słupia is a nearly 140-kilometer river, with its source near Sierakowska Huta, flowing through Słupsk and flowing into the Baltic Sea in Ustka. In its upper part it is about 7 m wide, but before it flows into the Baltic Sea, it spreads over 40 m wide. It flows through several lakes, including Lake Tuchlińskie, Trzebocińskie and Węgorzyno.
Słupia is a good place for canoeing enthusiasts. A 125-kilometer canoe trail runs from Lake Gowidlińskie to the mouth of the river. On the other hand, the 62-kilometer trail leading from Sulęczyn to Gałąźnia Mała was included in the list of national mountain canoeing routes. Along the trail there are stones commemorating John Paul II, who made his rafting here in 1964.
Part of the river valley has the status of a protected landscape park. Several reserves have been established here, in which there are rare species of birds, including white-tailed eagles