‘Urban growth’ refers to the process of growth and decline of economic agglomerations. The pattern of concentration of economic activity and its evolution have been found to be an important determinant, and in some cases the result, of urbanization, the structure of cities, the organization of economic activity, and national economic growth. The size distribution of cities is the result of the patterns of urbanization, which result in city growth and city creation. The evolution of the size distribution of cities is in turn closely linked to national economic growth.