The Congo River, formerly also known as the Zaire River, is the second-longest river in Africa, shorter only than the Nile, as well as the third-largest river in the world by discharge volume, following the Amazon and Ganges rivers. It is the world's deepest recorded river, with measured depths of around 220 m (720 ft). The Congo–Lualaba–Luvua–Luapula–Chambeshi River system has an overall length of 4,700 km (2,900 mi), which makes it the world's ninth-longest river. The Chambeshi is a tributary of the Lualaba River, and Lualaba is the name of the Congo River upstream of Boyoma Falls, extending for 1,800 km (1,100 mi).

The Kingdom of Kongo was a kingdom in Central Africa. It was located in present-day northern Angola, the western portion of the Democratic Republic of the Congo, Southern of Gabon and the Republic of the Congo. At its greatest extent it reached from the Atlantic Ocean in the west to the Kwango River in the east, and from the Congo River in the north to the Kwanza River in the south. The kingdom consisted of several core provinces ruled by the Manikongo, the Portuguese version of the Kongo title Mwene Kongo, meaning "lord or ruler of the Kongo kingdom", but its sphere of influence extended to neighboring kingdoms, such as Ngoyo, Kakongo, Loango, Ndongo, and Matamba, the latter two located in what is Angola today.