Koinadugu District is a district in the Northern Province of Sierra Leone. It is the largest District in Sierra Leone in geographical area, and one of the least most densely populated. Its capital and largest city is Kabala, which is also one of the main cities in Northern Sierra Leone. The District of Koinadugu has a population of 404,097, based on the 2015 Sierra Leone national census; and has a total area of . Koinadugu District is subdivided into eleven chiefdoms.