When talking about cities, you can never limit a city to its administrative unit only as the city developments don't recognize these boundaries thus the term often used is cosmopolitan area of a city rather than just the administrative unit. For example many dwellers in Nairobi who do business in the Nairobi CBD reside in areas that fall in the administrative areas of Kiambu, Machakos and Kajiado Counties but surprisingly they will say they live in nairobi. Which is correct because these are areas within the nairobi cosmopolitan area. Whereas the Nairobi cosmopolitan area has about 7 million dwellers, Nairobi city(administrative area) has about 4 million.