The sectoral, concentric zone and multiple nuclei ecological models of the industrial city enjoy only partial application to the city of Nairobi. Variations away from these idealised ecological models can be ascribed to the unique history of growth, social setting, and possibly geographic context of the city of Nairobi. It is material that this city has progressively evolved through the stages of a European, Colonial, Dual, and finally Hybrid African Industrial city [Jones 1980; O'Connor 1986; Hoselitz 1955; Clarke 1966; Skinner 1965; 1974; Soja 1968; McMaster 1968; Hovarth 1969; Obudho 1981; Brookfield 1975; Hake 1977; Kay & Smout 1977]. The pursuit of socio-spatial variation and therefore, residential segregation, and social stratification of the urban social function serves to give context to social cohesion by social inclusion or social exclusion-inequality, in the city of Nairobi. These two features, segregation and stratification, defining social cohesion by social inclusion or social exclusion-inequality, together with social cohesion by social capital. They constitute the seminal inherent aspects of the urban social function. Eighty percent (80%) of Nairobi's residential land carries less than 20% of the city's population. This group principally falls into the high-income bracket [and includes well over 90% of the non-indigenous peoples resident in the city, mainly Europeans and Asians], living in sub-urban planned residential areas [Obudho 1987]. Conversely over 60% of Nairobi's population resides in slums and squatter settlements and other illegal or low quality areas of the city. This population relegated into such derelict environments is almost all entirely indigenous African [Obudho 1987]. This profile is characteristic once more of the city's colonial legacy, of unequal access to opportunities and therefore differential growth. The growth and origins of Nairobi are capitalistic in nature, enshrining segregation of the three intertwined societies, African, Asian, and European. In these beginnings are embodied the seeds of the present reality, whereby the city lacks social integration, existing in three separate and distinct forms, each after it's respective social base. Sustenance of such an urban milieu is fraught with difficulties. The associated unequal endowment creates tensions, given its obvious manifestations in terms of differing levels of facilitation with the support amenities necessary for urban settlement. It is a matter of concern here to establish the spatial structures that have resulted from such a background and further delineate clearly their inherent social and environmental characteristics. The pressure on sustainable urban growth that emanates from the associated or inherent traits of such an urban spatial structure would thereby be better understood, for purposes of corrective prescription. The future sustainable urban growth of the city of Nairobi can only then be better guaranteed.