Mombasa County is one of the 47 counties of Kenya. It is the capital and the only city in the county of Mombasa.Initially it was one of the former districts of Kenya but in 2013 it was reconstituted as a county, on the same boundaries. It is the smallest county in Kenya, covering an area of 229.7 km2 excluding 65 km2 of water mass. The county is situated in the south eastern part of the former Coast Province. It borders Kilifi County to the north, Kwale County to the south west and the Indian Ocean to the east. Administratively, the county is divided into seven divisions, eighteen locations and thirty sub-locations.

Kenya was divided into eight provinces prior to 2013, which were subdivided into 47 counties. In the former Coast Province there are six counties, Mombasa being one of them. It is situated in the southeast of Coast Province. It is the smallest in size, covering an area of 212.5 km2. The county lies between latitudes 3°56′ and 4°10′ south of the equator and longitudes 39°34′ and 39°46′ east.