The Phoenix metropolitan area is new by national standards, having developed primarily since World War II and particularly since 1970. However, settlement patterns were established in the 1800s, in part due to topographic features such as water courses and mountains. The war effort during World War II stimulated the growth of the Valley. After the war, a combination of events led to much faster growth. These included the desire of ex-servicemen stationed in the area during the war to return; improvements in air conditioning; charter government in Phoenix, which allowed a small pro-growth business group to gain power; and
aerospace and electronics firms siting facilities, in part because of the federal government’s designation of Fort Huachuca as the principal proving ground for electronic defense equipment. The modern period began around 1970, when a maturing metro area coincided with the baby-boom generation reaching adulthood. The result was even more rapid growth that has continued to the current time. Rapid growth of the Phoenix metro area is expected to continue for at least the next 50 years. Land and water availability should not restrict growth until after the current population of nearly three million exceeds seven million in 2050.