Limits on city size and related topics

•Case studies of Charleston, SC and Portland, OR conclude that urban sprawl land use growth as reflected in night lights is almost impossible to manage.•Agglomeration is a positively reinforcing process that lies at the foundation of urban growth.•It is nearly impossible to countering agglomeration, with negative spillovers and weak local governments.•Urban futures include mega urban regions which dominant as rural and smaller cities decline.•This mega-urban equilibrium is dependent on new technology and its implementation. This paper examines several concepts and applications that influence city and urban development. The purpose is to explore the limits to city and urban growth. These urban expansions are reflected in the growth of Charleston SC and Portland OR through their changes in night light expression. These concepts include carrying capacity, growth or cordon boundaries, agglomeration, technological change and human ingenuity and innovation. A conclusion of this review is that history suggests that there is no strong evidence that urban growth can be limited either in scale or extent. Alternative urban futures are created with a no limits assumption due to the positive reinforcing effects of agglomeration as against the limiting assumption of controlled growth. However, technology and human ingenuity operate to produce a larger and more dispersed urban landscape. Discussion and conclusions follow this qualitative analysis.