Nairobi County is one of the 47 counties of Kenya. The third-smallest yet the most populous of the counties, it is coterminous with the city of Nairobi, which is also the capital and largest city of Kenya. It has 17 administrative sub-counties: Westlands, Dagoretti North, Dagoretti South, Langata, Kibra, Roysambu, Kasarani, Ruaraka, Embakasi South, Embakasi North, Embakasi Central, Embakasi East, Embakasi West, Makadara, Kamukunji, Starehe, and Mathare. According to the 2019 Kenya Population and Housing Census the population is 4,397,073 with a population density of 6,247/km2
