Siaya County has three major geomorphologic areas namely: Dissected Uplands, Moderate Lowlands and Yala Swamp. These have different relief, soils, and land-use patterns. The altitude of the County rises from 1,140m on the shores of Lake Victoria to 1,400m above sea level on the North.
Previously occupied by Bantu, Siaya would later become the heart of Dholuo who first entered Nyanza from Eastern part of Uganda as part of the series of migrations of the Nilotic speaking peoples. By the mid-18th century, several Luo groups expanded out of this area and spread over South Nyanza. The population movements were only halted by the imposition of British colonial control at the end of the 19th century when the areas of the various Luo subgroups at that moment were inscribed as the boundaries.
Aside from Got Ramogi Hill, there are many other beautiful hills found in the Siaya namely; Mbaga, Odiado, Akala, Regea, Nyambare, Usenge, Rambugu, Abiero, Sirafuongo, and Naya Hills. The combination of hills and lakes support a dizzying array of bird species making it an outstanding destination for ornithologists and a bird watchers paradise. The River Nzoia and River Yala traverse Siaya County before draining in Lake Victoria through the Yala Swamp.