When the Census Bureau in 1920 declared that the United States had become an urban society, it was a statement about statistical categories and not novel social and cultural
arrangements. Neither was it meant to forecast future trends. The number of people living in urban places-places of 2,500 people or more-had simply exceeded 50 percent of the national population. Almost four-fifths of the previous decade's population growth had occurred in urban places and, though immigration had diminished sharply, the great internal migration from country to city had continued unabated.