On the Niger at the head of the delta are Asaba (west bank) and Onitsha (east bank); Iddah (Ida), in the palm-oil zone; Lokoja on the west bank opposite the confluence with the Benue, and the headquarters of the protectorate's military force; Baro, on the east bank, 70 m.
Early in the 16th century the Igbira (Okpoto or Ibo) were one of the most powerful pagan peoples of Nigeria and had their capital at Iddah.
The stream, as far south as Iddah (Ida), a town on the east bank, rushes through a valley cut between the hills, the sandstone cliffs at some places rising 150 ft.
Between Iddah and Onitsha, 80 m., the banks are lower and the country flatter, and to the south of Onitsha the whole land is laid under water during the annual Delta.