Treska

thumb|Kayak track in the river thumb|Lake Matka

Treska (; ), is a river in the western part of North Macedonia, flowing for before joining the Vardar as its right tributary. With a basin covering 2,068 km2, the river originates high in the Stogovo mountain at about 2,000 metres elevation, initially flowing eastward through the Kičevo valley before making a sharp northward turn near Makedonski Brod and continuing through a narrow valley between the Suva Gora and Karadžica mountains to eventually meet the Vardar river near Skopje. The river system is known for its three major dams—Matka (built in 1937), Kozjak (2004), and Sveta Petka (2012)—as well as its diverse groundwater resources, which include isotropic aquifers in river valleys, fractured aquifers in mountainous regions, and particularly significant karst aquifers in limestone-rich areas that supply water to several towns in North Macedonia despite facing contamination risks from inadequate sewage infrastructure, unsanctioned landfills, intensive agriculture, and highland livestock farming.