River Basins are areas that are generally drained by a river and its tributaries are referred to as River Basin. River Basin can be grouped into three.
1. Large Basins with long Rivers — e.g. Niger and Benue River.
2. Rivers in Basin of Inland Drainage e.g. Yedseram river, Hadeija river etc.
3. Small Basins with short Rivers — e.g. Sound river, Osseo river Ossiomo and Ogun river.
N/B: Nigeria has about five major river basins and they are Niger Basin, Benue Basin, South Atlantic Basin, Cross River Basin and Chad Basin.