Kisii County is traversed by several permanent rivers which flow westwards into Lake Victoria. Among the notable river in Kisii County are Gucha, Mogusii, Riana, Mogonga and Iyabe Rivers. The probability of drought and floods is low because the Kisii’s highlands receive high reliable rainfall, and its soils are generally fertile and very productive.
The most notable features of these topographical zones are hills of Nyamasibi, Sameta, Kiamwasi, Kiong‘anyo, Kiongongi, Kiombeta, Sombogo, Nyanchwa, Taracha, and Kegochi hills. Kisii’s general slope of the land is from east to west.