Mathare Valley is a part of Mathare slum in Kenya. It is in the Nairobi area. Other informal settlements in the Nairobi area include Huruma, Kiambiu, Korogocho, Mukuru and Kibera. [1] It has a high population density. [2] It is a few kilometers from the centre of Nairobi. [3] Mathare River flows in the valley.