The Chambeshi (or Chambezi) River of northeastern Zambia is the most remote headstream of the Congo River (in length) and therefore considered its source. (However, by volume of water, the Lualaba River is the greater "source" of the Congo.)

The Chambeshi rises as a stream in the mountains of northeast Zambia near Lake Tanganyika at an elevation of 1760 metres above sea level. It flows for 480km into the Bangweulu Swamps, which are part of Lake Bangweulu, and by the end of the rainy season in May, it delivers a flood which recharges the swamps and inundates a vast floodplain to the southeast, supporting the Bangweulu Wetlands ecosystem. The water then flows out of the swamps as the Luapula River.