Regions of the United States/Economics, agriculture and industry
Economic activity is a strong force for regionalization. Ohmae, in The Rise of the Region State, argues that regions are "drawn by the deft but invisible hand of the global market for goods and services. ... Region states are natural economic zones."
To Ohmae, region states have between five million and 20 million people. They are "small enough for ... citizens to share certain economic and consumer interests but of adequate size to justify the infrastructure". This infrastructure is a link to the global economy: an international airport, a large harbor, a market for purchase and consumption of imported goods.