The river's name is said to come from a mispronunciation of "nsao'loonga", the local name of a bird.

[1] The Salonga River meanders in a generally northwest direction through the Salonga National Park and on to its confluence with the Busira River.

[2] The Salonga National Park is the largest forest national park in Africa, with an area of 33,350 square kilometres (12,880 sq mi).

[1] The river enters the Busira 2 kilometres (1.2 mi) upstream from Lotoko.

It is navigable all year with 50 ton barges up to Watsi-Kengo.