Kenya has a total of 47 counties with each covering a specific area and having unique code. As of 2018-2019 the following list of counties exist in the country.The biggest county is Turkana with a total of 71,597.80 Kilometres.The smallest county in Kenya is Mombasa with 212.5 kilometres.
| Code | County | Former Province | Area (km2) | Population | Capital |
| Census (2009) | |||||
| 1 | Mombasa (County) | Coast | 212.5 | 939,370 | Mombasa (City) |
| 2 | Kwale | Coast | 8,270.30 | 649,931 | Kwale |
| 3 | Kilifi | Coast | 12,245.90 | 1,109,735 | Kilifi |
| 4 | Tana River | Coast | 35,375.80 | 240,075 | Hola |
| 5 | Lamu | Coast | 6,497.70 | 101,539 | Lamu |
| 6 | Taita–Taveta | Coast | 17,083.90 | 284,657 | Mwatate |
| 7 | Garissa | North Eastern | 45,720.20 | 623,060 | Garissa |
| 8 | Wajir | North Eastern | 55,840.60 | 661,941 | Wajir |
| 9 | Mandera | North Eastern | 25,797.70 | 1,025,756 | Mandera |
| 10 | Marsabit | Eastern | 66,923.10 | 291,166 | Marsabit |
| 11 | Isiolo | Eastern | 25,336.10 | 143,294 | Isiolo |
| 12 | Meru | Eastern | 6,930.10 | 1,356,301 | Meru |
| 13 | Tharaka-Nithi | Eastern | 2,409.50 | 365,330 | Kathwana |
| 14 | Embu | Eastern | 2,555.90 | 516,212 | Embu |
| 15 | Kitui | Eastern | 24,385.10 | 1,012,709 | Kitui |
| 16 | Machakos | Eastern | 5,952.90 | 1,098,584 | Machakos |
| 17 | Makueni | Eastern | 8,008.90 | 884,527 | Wote |
| 18 | Nyandarua | Central | 3,107.70 | 596,268 | Ol Kalou |
| 19 | Nyeri | Central | 2,361.00 | 693,558 | Nyeri |
| 20 | Kirinyaga | Central | 1,205.40 | 528,054 | Kerugoya / Kutus |
| 21 | Murang’a | Central | 2,325.80 | 942,581 | Murang’a |
| 22 | Kiambu | Central | 2,449.20 | 1,623,282 | Kiambu |
| 23 | Turkana | Rift Valley | 71,597.80 | 855,399 | Lodwar |
| 24 | West Pokot | Rift Valley | 8,418.20 | 512,690 | Kapenguria |
| 25 | Samburu | Rift Valley | 20,182.50 | 223,947 | Maralal |
| 26 | Trans-Nzoia | Rift Valley | 2,469.90 | 818,757 | Kitale |
| 27 | Uasin Gishu | Rift Valley | 2,955.30 | 894,179 | Eldoret |
| 28 | Elgeyo-Marakwet | Rift Valley | 3,049.70 | 369,998 | Iten |
| 29 | Nandi | Rift Valley | 2,884.50 | 752,965 | Kapsabet |
| 30 | Baringo | Rift Valley | 11,075.30 | 555,561 | Kabarnet |
| 31 | Laikipia | Rift Valley | 8,696.10 | 399,227 | Nanyuki |
| 32 | Nakuru | Rift Valley | 7,509.50 | 1,603,325 | Nakuru |
| 33 | Narok | Rift Valley | 17,921.20 | 850,920 | Narok |
| 34 | Kajiado | Rift Valley | 21,292.70 | 687,312 | Kajiado |
| 35 | Kericho | Rift Valley | 2,454.50 | 752,396 | Kericho |
| 36 | Bomet | Rift Valley | 1,997.90 | 730,129 | Bomet |
| 37 | Kakamega | Western | 3,033.80 | 1,660,651 | Kakamega |
| 38 | Vihiga | Western | 531.3 | 554,622 | Vihiga |
| 39 | Bungoma | Western | 2,206.90 | 1,375,063 | Bungoma |
| 40 | Busia | Western | 1,628.40 | 743,946 | Busia |
| 41 | Siaya | Nyanza | 2,496.10 | 842,304 | Siaya |
| 42 | Kisumu | Nyanza | 2,009.50 | 968,909 | Kisumu(City) |
| 43 | Homa Bay | Nyanza | 3,154.70 | 963,794 | Homa Bay |
| 44 | Migori | Nyanza | 2,586.40 | 917,170 | Migori |
| 45 | Kisii | Nyanza | 1,317.90 | 1,152,282 | Kisii |
| 46 | Nyamira | Nyanza | 912.5 | 598,252 | Nyamira |
| 47 | Nairobi (County) | Nairobi (Province) | 694.9 | 3,138,369 | Nairobi (City) |
| 581,309.00 | 38,610,097 | Nairobi |
