Isiolo County is a county in the former Eastern Province of Kenya. Its capital and largest town is Isiolo. It borders Marsabit County to the north, Wajir County to the east, Garissa and Tana River counties to the south east, Meru County to the south, Laikipia County to the south west and Samburu County to the west. It has three administrative sub-counties: Garbatulla, Isiolo and Merti. According to the 2019 Kenya Population and Housing Census the population is 268,002 with a population density of 11/km2.

