Code Links to County Website  Former Province Area (km2) Population
Census (2009)
Population
Census (2019)
Capital
1 Mombasa Coast 212.5 939,370 1,208,333 Mombasa (City)
2 Kwale Coast 8,270.3 649,931 866,820 Kwale
3 Kilifi Coast 12,245.9 1,109,735 1,453,787 Kilifi
4 Tana River Coast 35,375.8 240,075 315,943 Hola
5 Lamu Coast 6,497.7 191,539 143,920 Lamu
6 Taita–Taveta Coast 17,083.9 284,657 340,671 Mwatate
7 Garissa North Eastern 45,720.2 623,060 841,353 Garissa
8 Wajir North Eastern 55,840.6 661,941 781,263 Wajir
9 Mandera North Eastern 25,797.7 1,025,756 867,457 Mandera
10 Marsabit Eastern 66,923.1 291,166 459,785 Marsabit
11 Isiolo Eastern 25,336.1 143,294 268,002 Isiolo
12 Meru Eastern 7,003.1 1,356,301 1,545,714 Meru
13 Tharaka-Nithi Eastern 2,609.5 365,330 393,177 Kathwana
14 Embu Eastern 2,555.9 516,212 608,599 Embu
15 Kitui Eastern 24,385.1 1,012,709 1,136,187 Kitui
16 Machakos Eastern 5,952.9 1,098,584 1,421,932 Machakos
17 Makueni Eastern 8,008.9 884,527 987,653 Wote
18 Nyandarua Central 3,107.7 596,268 638,289 Ol Kalou
19 Nyeri Central 2,361.0 693,558 759,164 Nyeri
20 Kirinyaga Central 1,205.4 528,054 610,411 Kerugoya /Kutus
21 Murang’a Central 2,325.8 942,581 1,056,640 Murang’a
22 Kiambu Central 2,449.2 1,623,282 2,417,735 Kiambu
23 Turkana Rift Valley 71,597.8 855,399 926,976 Lodwar
24 West Pokot Rift Valley 8,418.2 512,690 621,241 Kapenguria
25 Samburu Rift Valley 20,182.5 223,947 310,327 Maralal
26 Trans-Nzoia Rift Valley 2,469.9 818,757 990,341 Kitale
27 Uasin Gishu Rift Valley 2,955.3 894,179 1,163,186 Eldoret
28 Elgeyo-Marakwet Rift Valley 3,049.7 369,998 454,480 Iten
29 Nandi Rift Valley 2,884.5 752,965 885,711 Kapsabet
30 Baringo Rift Valley 11,075.3 555,561 666,763 Kabarnet
31 Laikipia Rift Valley 8,696.1 399,227 518,560 Rumuruti
32 Nakuru Rift Valley 7,509.5 1,603,325 2,162,202 Nakuru
33 Narok Rift Valley 17,921.2 850,920 1,157,873 Narok
34 Kajiado Rift Valley 21,292.7 687,312 1,117,840 Kajiado
35 Kericho Rift Valley 2,454.5 752,396 901,777 Kericho
36 Bomet Rift Valley 1,997.9 730,129 875,689 Bomet
37 Kakamega Western 3,033.8 1,660,651 1,867,579 Kakamega
38 Vihiga Western 531.3 554,622 590,013 Vihiga
39 Bungoma Western 2,206.9 1,375,063 1,670,570 Bungoma
40 Busia Western 1,628.4 743,946 893,681 Busia
41 Siaya Nyanza 2,496.1 842,304 993,183 Siaya
42 Kisumu Nyanza 2,009.5 968,909 1,155,574 Kisumu(City)
43 Homa Bay Nyanza 3,154.7 963,794 1,131,950 Homa Bay
44 Migori Nyanza 2,586.4 917,170 1,116,436 Migori
45 Kisii Nyanza 1,317.9 1,152,282 1,266,860 Kisii
46 Nyamira Nyanza 912.5 598,252 605,576 Nyamira
47 Nairobi (County) Nairobi (Province) 694.9 3,138,369 4,397,073 Nairobi (City)
581,309.0 38,610,997 47,564,296 Nairobi