| Ward name | Approx. Population | Approx. area in square km |
| Mumias central | 37214 | 33.6 |
| Mumias north | 15765 | 35.7 |
| Etenje | 28162 | 50.6 |
| Musanda | 30721 | 45.4 |
Mumias West
Approx. Population : 111862, Approx. Area in square km: 165.3, Wards – Mumias central, Mumias north, Etenje, Musanda Ward name Approx.