As early as 300 BC, the dry desert soil began yielding crops for the Hohokam people, who spent centuries developing a complex system of irrigation canals, only to mysteriously abandon them around 1450 AD. Remnants of the canals can be seen in the Pueblo Grande Museum.
Later, small groups of Pima and Maricopa Indians eked out an existence along the Gila and Salt Rivers, but there were no more permanent settlements until the mid-1860s, when the US Army built Fort McDowell northeast of Phoenix. This prompted former soldier and prospector Jack Swilling to reopen Hohokam canals to produce crops for the garrison and led to the establishment of a town in 1870. Darrel Duppa, a British settler, suggested that the town had risen from the ashes of the Hohokam culture like the fabled phoenix, and the name stuck. Meanwhile, Charles Trumbull Hayden established a ferry crossing and trading post on the Salt River, southeast of Phoenix. Duppa, again putting his knowledge of the classics to work, commented that the location reminded him of the Vale of Tempe near Mt Olympus in Greece and, once again, his suggestion stuck.
Phoenix quickly established itself as an agricultural and transportation centre. The railway arrived from the Pacific in 1887 and by the time Phoenix became the territorial capital in 1889, it had about 3000 inhabitants. Tempe, too, was growing, and in 1886 the Arizona Normal School was established here, later to become Arizona State University (ASU). Other villages began to grow; Mesa was founded by Mormon settlers in 1878, and Scottsdale followed a decade later, named after army chaplain Winfield Scott, one of its first settlers.
The lack of water remained a major stumbling block to further growth until 1911, when construction workers finished building the Roosevelt Dam on the Salt River, the first of many large dams to be built in the state. The stage was set for growth and grow Phoenix did.
In 1926, Phoenix's railway link became transcontinental, enabling people from the East to pour into the state in increasing numbers. Many came for recreation - to stay in dude ranches and be cowboys for a few weeks, or to relax at the luxurious Arizona Biltmore resort, opened in 1929 and still one of the finest in the West. Others came for their health; the dry desert air was said to cure various respiratory ailments. Many of these visitors stayed, including Dwight and Maie Heard, who arrived in 1895 to cure Dwight's lung complaints. He became a leading businessman and editor, and with his wife, founded Phoenix's most interesting museum, the Heard.
The early history of the area is not immediately evident to most visitors, who see a sprawling modern city. The two major causes of this pervasive modernity were the advent of air conditioning after WWII and the diversion of Colorado River water to Phoenix after 1968. Between WWII and today, the valley's population has grown almost sixfold; in the 1980s more than 100,000 new residents were arriving each year, making this the country's fastest growing area. Modern buildings have replaced most but not all of the old ones.
The valley's economy continues to be driven by politics, agriculture, transportation and tourism, but recent growth has brought industry and manufacturing, especially of electrical and computer components, to the economic foreground.
The economic dips of 2000 and 2001 hit the manufacturing and tourism sectors hardest, but Phoenix's economy remained strong, and in 2002 the Valley's population grew by 90,000. The population surge buoyed the real estate and construction industries, which kept the city's economy buzzing, consolidating Phoenix's deserved reputation for being one of the West's latter-day boomtowns.