During the Later Iron Age period in Kenya, communities that built structures known in the local language as ohingni (singular - ohinga)' occupied the Lake Victoria region in south-western Kenya. The term refers to both stone-built and earth-built settlement enclosures widely distributed in the Nyanza region, that were abandoned before and during the colonial period. Their distribution and contents, in terms of archaeological remains and use of space, indicate that they were the main focus of an extensive settlement system that flourished during the pre-colonial period (Chittick 1965; Lofgren 1967; Odede 1998; Onjala 1990; Wandibba 1986). In this paper, based on fieldwork conducted in the early 1990s, I summarise the basic distribution of the structures within four areas of the Lake Victoria region. I also suggest that particular historical, social and environmental factors contributed to the patterns visible in the archaeological record and that human environment interactions as well as changing group relationships provide the key to understanding the nature of this particular settlement system.