In 1867, when Jack Swilling stopped to rest his horse at the foot of the White Tank Mountains, his eyes caught the rich gleam of brown, dry soil turned up by his horse's hooves. He saw farm land, predominately free of rocks, and in a place beyond the reach of heavy frost or snow. All it needed was water, so he formed the Swilling Irrigation and Canal Company and dug a large canal that drew in river water. The Board of Supervisors in Yavapai County officially recognized the new town on May 4, 1868, and the first post office was established the following month with Swilling as the postmaster.

During the 1930s, Phoenix and its surrounding area began to be called "The Valley of the Sun", which was an advertising slogan invented to boost tourism.

On June 26, 1990, the temperature reached an all-time record high of 122 °F (50 °C).

The Hohokam people created roughly 135 miles (217 kilometers) of irrigation canals, making the desert land arable. The paths of these canals were later used for the Arizona Canal, Central Arizona Project Canal, and the Hayden-Rhodes Aqueduct. They also carried out extensive trade with the nearby Ancient Puebloans, Mogollon, and Sinagua, as well as with the more distant Mesoamerican civilizations. It is believed periods of drought and severe floods between 1300 and 1450 led to the Hohokam civilization's abandonment of the area. The name "Phoenix" was chosen to describe a city born from the ruins of a former civilization.

When the Mexican-American War ended in 1848, Mexico ceded its northern zone to the United States, and the region's residents became U.S. citizens. The Phoenix area became part of the New Mexico Territory. On February 24, 1863, during the Civil War, Congress passed the "Arizona Organic Act", which split off the western portion of the 12-year-old New Mexico Territory as the new Arizona Territory.

Harming or vandalizing saguaros in any manner, such as shooting them (sometimes known as "cactus plugging") is illegal by state law in Arizona and punishable by up to 25 years in jail. When houses or highways are built, special permits must be obtained to move or destroy any saguaro affected by the construction.

Each winter 400,000 "snowbirds" temporarily migrate to Phoenix for the sunny climate and magnificent desert scenery.

Baseball fans eagerly await spring training each year, when 15 MLB teams gather in the Phoenix area for what is affectionately referred to as the Cactus League.

Haboobs are giant walls of dust created from high winds rushing out of a collapsing thunderstorm. According to the National Weather Service, Phoenix experiences an average of three haboobs each year.

The territorial capital moved from Prescott to Phoenix in 1889. On February 14, 1912, Phoenix became a state capital, as Arizona was admitted to the Union as the 48th state. Today, it is the largest state capital by population.