The Iullemmeden Basin (Berber language: Iwellemmedden) is a major sub-Saharan inland basin in West Africa, extending about 1,000 kilometres (620 mi) north to south and 800 kilometres (500 mi) east to west.

It covers western Niger and parts of Algeria, Mali and Nigeria.

It is named after the Iullemmeden, a federation of Tuareg people who live in the central region of Niger.

[1] The sediments from Cambrian to Pleistocene times are 1,500 to 2,000 metres (4,900 to 6,600 ft) thick, with alternating layers formed when the basin was undersea and above sea level.

Potentially valuable minerals include uranium and copper ores and coal and salt deposits.