Nairobi County has the highest number of people, followed by Kiambu,Nakuru,Kakamega respectively. The counties with lowest number of people include Lamu,Isiolo,Samburu,Tana River and Taita Taveta.
The number of people per county was provided by the Kenya National Bureau of Statistics based on the Census Report.
Here is a table showing the number of people per county,the most populous and least populous counties in Kenya.
| NAME OF COUNTY | Total Number of People |
| NAIROBI | 4,397,073 |
| KIAMBU | 2,417,735 |
| NAKURU | 2,162,202 |
| KAKAMEGA | 1,867,579 |
| BUNGOMA | 1,670,570 |
| MERU | 1,547,714 |
| KILIFI | 1,453,767 |
| MACHAKOS | 1,421,932 |
| KISII | 1,266,860 |
| MOMBASA | 1,208,333 |
| UASIN GISHU | 1,163,186 |
| NAROK | 1,157,873 |
| KISUMU | 1,155,574 |
| KITUI | 1,136,167 |
| HOMA BAY | 1,131,950 |
| KAJIADO | 1,117,840 |
| MIGORI | 1,116,436 |
| MURANGA | 1,056,640 |
| SIAYA | 993,183 |
| TRANS NZOIA | 990,341 |
| MAKUENI | 987,653 |
| TURKANA | 926,976 |
| KERICHO | 901,777 |
| BUSIA | 893,681 |
| NANDI | 885,711 |
| BOMET | 875,689 |
| MANDERA | 867,457 |
| KWALE | 866,820 |
| GARISSA | 841,353 |
| WAJIR | 781,263 |
| NYERI | 750,164 |
| BARINGO | 666,763 |
| NYANDARUA | 638,289 |
| WEST POKOT | 621,241 |
| KIRINYAGA | 610,411 |
| EMBU | 608,599 |
| NYAMIRA | 605,576 |
| VIHIGA | 590,013 |
| LAIKIPIA | 518,560 |
| MARSABIT | 459,785 |
| ELGEYO MARAKWET | 454,480 |
| THARAKA NITHI | 393,177 |
| TAITA/TAVETA | 340,671 |
| TANA RIVER | 315,943 |
| SAMBURU | 310,327 |
| ISIOLO | 266,002 |
| LAMU | 143,920 |
