The Šešupė River is a significant waterway located in southeastern Lithuania and western Poland. It flows for approximately 140 kilometers, eventually joining the Neman River. The river is known for its picturesque landscapes and diverse ecosystems, making it an important natural resource in the region. The Šešupė River serves as a natural border between Lithuania and Poland for part of its course. It is also a popular spot for recreational activities such as fishing and kayaking. The river's basin supports various wildlife, contributing to the area's biodiversity and ecological health.