The Aar (German Aare), a tributary of the High Rhine, is the longest river that both rises and ends entirely within Switzerland.

Its total length from its source to its junction with the Rhine comprises about 295 km (183 miles), during which distance it descends 1,565 m (5,135 ft), draining an area of 17,779 km2 (6,865 sq mi), including the whole of central Switzerland.

Read more about Aar:  Course, Tributaries, Reservoirs, History