The Niamey region straddles between the Liptako, corresponding to the northern extremity of the East ridge of Man, and the south-western edge of the Iullemmeden basin. Covering an area of over , the metropolitan area sits atop two plateaux reaching  in altitude, bisected by the Niger River. At Niamey, the river, running almost straight SSE from Gao, Mali, makes a series of wide bends. The city was founded on the east ("left bank") of the river as it meanders from west to east flow to run almost directly south. A series of marshy islands begin at Niamey and extend south in the river.