The growth of defense industries, a non-unionized labor force, and the spread of air-conditioning all helped spur economic development and population growth in the Southwest and the South. This made the Sun Belt the fastest-growing region of the country between 1940 and 1980.

READING THE MAP Which states experienced population growth of more than 20 percent? Which states experienced the largest population growth?

CONNECTIONS What stimulated the population boom in the Southwest? What role did the Cold War play in this expansion? What developments made the Southwest diverse in the composition of its population?