The River Niger is the most important river in Nigeria and it is the third longest in Africa. The Niger rises from the Futa Jallon Highland to the north-east of Sierra-Leone and front two-third of its length of 4,169 kilometers, flows through other countries, it enters Nigeria from the west and then runs south easterly to Lokoja, confluence venue with the River Benue, its principal tributary.

The other main tributaries of the River Nigeria are the Sokoto, Kaduna and Anambra Rivers. From Lokoja, the Niger flows southwards to the Delta, splitting into numerous interlacing channels to empty itself into the Gulf of Guinea.

The Benue River, which has its source in the Cameroon Republic, flows south-westerly to its confluence with the Niger, receiving in its course the waters of Rivers Katsina and Gongola.

A Lake, with an area of 1,236 square kilometers, was created on the River Niger by the construction of the Kainji hydro-electric dam, about 112 kilometers north of Jebba.

The dam, which is also being used to control the flow of the Niger flood waters, has now made the river navigable throughout the year from Escravos to Niamey in the Niger Republic, a distance of more than 1,600 kilometers. Along the coast, there are many rivers but the following are the most important:

1. The Ogun River which flows into the Lagos Lagoon;  

2. The Delta River in which now stands the modern port of Sapele;  

3. The Escrovo, the Forcados and Sombrecro, the Bonny River which provides Port Harcourt with an outlet to the Cross River network which includes the Imo and Qua-Iboe Rivers.