The earliest known culture lived in the region we now know as Arizona approximately, 25,000 B.C. A later culture, the Hohokam (A.D. 500–1450), were pit dwellers who constructed extensive irrigation systems. The Pueblo flourished in Arizona between the 11th and 14th centuries and built elaborate cliff dwellings that still stand today. The Apache and Navajo people came to Arizona from Canada c.1300 where some of their descendants remain today.

The Arizona region came under Mexican control following the Mexican war of independence from Spain (1810–21).

In the Treaty of Guadalupe Hidalgo (1848), Mexico relinquished control of the area N of the Gila River to the United States. This area became part of the U.S. Territory of New Mexico in 1850. The United States, wishing to build a railroad through the area south of the Gila River, bought the area between the river and the south boundary of Arizona from Mexico in the Gadsden Purchase (1853). Arizona's minerals attracted most of the early explorers to this newly acquired area. Although the area remained a relatively obscure section of the New Mexico territory, mining continued as small numbers of prospectors, crossing Arizona to join the California gold rush, found gold, silver, and a neglected metal—copper.

In 1863, Arizona was organized as a separate territory, with its first capital at Fort Whipple. The city of Prescott was later named the capital in 1865. The capital was once again moved to Tucson in 1867, back to Prescott in 1877, and finally to Phoenix in 1889.

In the 1870s mining flourished, and by the following decade the Copper Queen Company at Bisbee was exploiting one of the area's largest copper deposits. In 1877 silver was discovered at Tombstone setting off a boom that lasted less than 10 years yet drew throngs of prospectors to Arizona. Tombstone also became famous for its lawlessness; Wyatt Earp and his brothers gained their reputations during the famous gunfight at the O. K. Corral (1881).

By 1880 the Santa Fe and Southern Pacific railroads both extended into Arizona. Ranching began to thrive and sheep rising grew from solely a Navajo occupation to a major.

In 1912, President Taft signed the bill that allowed Arizona to attain statehood.

By 1900, diverted Arizona rivers were irrigating 200,000 acres. The opening of the Roosevelt Dam in 1911 ushered in massive irrigation projects that transformed Arizona's valleys.

During World War II, defense industries were established in Arizona. Manufacturing, notably electronic industries, continued to develop after the war, especially around Phoenix and Tucson; in the 1960s, manufacturing achieved economic supremacy over mining and agriculture in Arizona. During the 1970s and 80s the state experienced phenomenal economic growth as it and other Sun Belt states attracted high-technology industries with enormous growth potential.