The African river system ranked ninth by length and including the Lualaba is the Congo system.
The Congo–Lualaba–Luvua–Luapula–Chambeshi system is measured from the Chambeshi headwaters through connected waterways that eventually become the Lualaba and then the Congo River. At Boyoma Falls near Kisangani, the upstream river is conventionally called the Lualaba; downstream, it is known as the Congo. This full system is listed as the world’s ninth-longest river system.
The Congo is Africa’s second-longest river after the Nile and carries more water than any other African river. It also has the world’s deepest recorded river channel in places. A frequent mistake is treating the Lualaba as an unrelated river: it is the upper course of the Congo system under a different regional name. The Chambeshi is significant because some length rankings trace the system’s ultimate source there.