Rivers

The Congo River is the largest river in Western Central Africa. Its overall length of 4,380 km makes it the second longest in Africa. The river and its tributaries flow through the second largest rain forest area in the world, only the Amazon Rainforest being larger. The river also has the second-largest flow in the world, behind the Amazon, and the second-largest watershed of any river, again trailing the Amazon and slightly ahead of the Mississippi.

The sources of the Congo are in the highlands and   mountains of East Africa Rift, as well as Lake Tanganyika and Lake Mweru, which feed the Lualaba River, which then becomes the Congo below Boyoma Falls.

The Congo flows generally west from Kisangani just below the falls, then gradually bends southwest, passing by Mbandaka, joining with the Ubangi River, and running into the Pool Malebo. Kinshasa and Brazzaville are on opposite sides of the river at the Pool, and then the river narrows and falls through a number of cataracts in deep canyons running by Matadi and Boma, and into the sea at the small town of Muanda.

Nearly the entire Congo is readily navigable, and with railways now bypassing the three major falls, much of the trade of central Africa passes along it, including  copper,  palm oil (as kernels), sugar, coffee, and  cotton. The river is also potentially valuable for hydroelectric power, and the Inga facility below Pool Malebo is the first to exploit the river.
In February 2005 South Africa's Eskom, announced a proposal to drastically increase the capacity of the Inga facility through improvements and the construction of a new hydroelectric dam. The project would bring the maximum output of the facility to 40 GW, double that of China's Three Gorges Dam.
Some information on numerous Ports on the Congo River and their Caracteristics.

The river transport in the DRC is constituted of 16238 km of navigable river network and 40 ports.
The primary water corridor in Congo is represented by the Congo River divided in two series of falls in three navigable reach. The middle reach from Kinshasa to Kisangani is the most important one; with 1734 Km. the remaining reach are the higher stretch form Kongolo to malemba Nkulu and the lower stretch from Kisangani to Kindu 550 km, important lakes with considerable traffics are represented by the lakes Tanganyika, Kivu and Maidombe, Albert and Mweru.

North DRC

The Sangha River:
A river in central Africa is a tributary of the Congo River. It flows through Cameroon, the Republic of Congo, and the Central African Republic.
Its tributaries include the Ngoko, Mambere, and the Kadei. Coffee is raised on plantations along the Sangha.

The Ubangi River:
(Also Oubangi) is a major tributary of the Congo River in central Africa. It is considered to begin at the junction of the Mbomou and Uele Rivers, flows west for about 350 km, then bends to the southwest, passes through Bangui, then flows south for another 500 km to the Congo. From its start to 100 km below Bangui, the Ubangi defines the boundary between the Central African Republic and the Democratic Republic of the Congo (DRC). Thereafter, it forms the boundary between the DRC and the Republic of Congo until it empties into the Congo River.

The Uele River:
A River in the Democratic Republic of the Congo. It is a tributary of the Ubangi River, which in turn flows into the Congo

The Mbomou River:
Forms part of the boundary between the Central African Republic (CAR) and the Democratic Republic of the Congo (DRC). The Mbomou merges with the Uele River to form the Ubangi River. The Ubangi, a tributary of the Congo, also serves as part of the border between the CAR and the DRC.

The Lulonga:
The lulonga is a river in the Equateur province. It is about 200 km long from its beginning at the town of Basankusu. There the Lopori and the Maringa join to form the Lulonga. The Lulonga River flows into the Congo River at the town Lulonga.

Central DRC

The Kasai River:

The Kasai River is a river in central Africa. The river begins in Angola. Part of the river serves as the border between Angola and the Democratic Republic of the Congo (DRC). It then flows into the DRC, where it empties into the Congo River.
The Kasai's tributaries include the Fimi, Kwango, and Sankuru rivers. The short stretch of the Kasai from the inflow of the Fimi to the Congo is known as the Kwa River.

The Fimi River:

The Fimi River flows from Lake Mai-Ndombe to the Kasai River, which in turn empties into the Congo.

South DRC

The watershed of the Ituri/Aruwimi is almost entirely dense forest, with just a handful of villages along its course, and crossed by roads in about four places. The cataracts above Yambuya make it impossible to use the river for navigation.