Map from the Common Census Project showing the "spheres of influence" of cities in the US. The question asked was, "On the level of North America as a whole, what major city do you feel has the most cultural and economic influence on your area overall?".
US Megaregions - 2050. Most of nation's rapid population growth, and an even larger share of its economic expansion, is expected to occur in 10+ emerging megaregions. Megaregions are defined by layers of relationships that together define a common interest; this common interest, in turn, forms basis for policy decisions: • Environmental systems and topography • Infrastructure systems • Economic linkages • Settlement patterns and land use • Shared culture and history