According to Levy, there are that led to the rapid increase in number and the size of urban centers in the United States in the 19th and 20th century. The principle reason for the rapid growth in urban centers was the increased national population.
The overwhelming population increase was as a result of immigration as well as the natural increase. However, Levy notes that the rate of urban growth was much higher compared to the rate of national growth possibly because of other factors. He points out that one of these factors was the advent of industrial revolution in the 19th century. The introduction of machines in the farms resulted into a capital intensive agricultural productions which was more profitable. Consequently, the people in the rural areas started migrating to the urban centers in search for jobs in the fast developing industries (Levy, pg 10).