The county lies between 914m above sea level (ASL) in the East and 3,353m above sea level (ASL) along the slopes of the Aberdare Mountains in the West. The highest areas in the west have deeply dissected topography and are drained by several rivers. All the rivers flow from the Aberdare ranges to the West, South Eastward to join Tana River.
Murang’a is also the source of Rivers Maragua, which originates from the heart of the Aberdare Range, Mathioya, Kayahwe, Irati and Muriurio among others.