Čepkeliai marsh (Lithuanian: Čepkelių raistas) is the largest swamp in Lithuania, in the territory of Dzūkija National Park. Located south of Marcinkonys village and north of Kotra River, which flows along the Belarus-Lithuania border in this area.
The area of the swamp is protected as a natural reserve and part of the cross-border wetlands of international importance: Kotra Ramsar site and Cepkeliai Ramsar site
Coordinates: 54°0′N 24°31′E / 54.000°N 24.517°E