Regional urbanization and the selective growth of towns in North American regions

Despite the extensive discussion of urbanization in the North American past, the processes of selective growth among the various towns and cities, which comprise a regional urban system, remain obscured by the use of oversimplified explanations that neglect either functional and locational variations among the centres or the changing conditions of regional development. A generalized model of selective urban growth in newly settling regions is proposed which distinguishes three periods of development by characteristics of circulation and export activity. It emphasizes the changing implications of town locations (their nodality) as settlement expands and the bases of urban growth shift from commercial and local services to increasingly manufacturing. Discussion of the literature on regional urbanization, organized under five categories of traditional and more recent explanations of selective growth, not only points to the temporal and locational deficiencies which the model addresses, but also reveals the need for closer examination within a developmental framework of both the interdependencies of central place and mercantile bases of urban growth and the relationships between the emergence of manufacturing and city sizes.