Kakamega and Bungoma Counties are among the five most populous Counties in Kenya according to Census 2019 results released by KNBS. The County with the largest population is Nairobi, 4,397,073, followed by Kiambu County, 2,417,735, then Nakuru County, 2,162,202, followed by Kakamega County with a population of 1,867,579, then Bungoma County, 1,670,570. The least populated Counties are Lamu with 143,920 people, Isiolo, with a population of 268,002, Samburu with a population of 310,327, Tana River 315,943 and Taita Taveta with 340,671.
Apart from Kakamega and Bungoma Counties, the population in other Counties in Western is as follows; Vihiga County, 590,013, Busia County the population is 893,681, in Trans Nzoia County, the population stands at 990,341, and in neighboring West Pokot, Uasin Gishu and Nandi Counties, the population stands at 621,241, 1,163,186 and 885,711 respectively.
In Kakamega, the male population is 897,133, the female population is 970,406 while intersex is 40. In Bungoma County, the male population is 812,146, the female population is 858,389 while intersex is 35. In Busia, the male population stands at 426,252, the female population stands at 467,401 and the intersex population is 28. In Vihiga County, the male population is 283,678, the female population is 306,323 while the intersex number is 12. In Trans Nzoia County, the male population is 489,107, the female population is 501,206 while the intersex population is 28. In West Pokot, the male population stands at 307,013, the female population stands at 314,213 while the intersex are 15.