Phoenix is the capital and most populous city in the U.S. state of Arizona, situated within the Salt River Valley and the broader Arizona Sun Corridor. Located in the northeastern reaches of the Sonoran Desert, it serves as the county seat of Maricopa County. The city occupies a vast area of 517.9 square miles, making it the largest city by area in Arizona and the eleventh-largest in the United States. Its geographic position places it at the confluence of the Salt and Gila Rivers, a location that has historically defined its agricultural and developmental trajectory.

The modern settlement began in 1867 when Jack Swilling established an irrigation canal system to support farming for nearby mining towns. Named by settler Lord Darrell Duppa to signify rebirth from the ruins of the ancient Hohokam civilization, the town was officially recognized in 1868 and incorporated as a city in 1881 with a population of approximately 2,500. Phoenix became the capital of the Arizona Territory in 1889, a status it retained when Arizona achieved statehood. The arrival of the railroad in the 1880s transformed it into a major trade center, connecting the region to eastern and western markets.

As the cultural center of Arizona, Phoenix is defined by its grid-layout downtown core and its role as a primary political and economic hub for the American Southwest. The city's early economy was anchored by the Five C's: cotton, cattle, citrus, climate, and copper. While high-tech companies began moving into the valley after World War II, the region remains deeply connected to its agricultural roots. The area has merged with neighboring cities like Scottsdale and Tempe to form a sprawling metropolitan landscape that includes rapidly developing exurbs.

Visitors are drawn to Phoenix for its warm, sunny winter weather which supports a thriving tourism industry, as well as its unique desert environment. The city offers access to the remnants of Hohokam canal systems and extensive trade history with Mesoamerican civilizations. Its hot, dry climate features long, hot summers with average daytime highs reaching 107 °F and very mild winters, occasionally seeing temperatures in the 30s°F. This distinct weather pattern has historically attracted relocation from Eastern and Midwestern states.

The city had a population of 1,608,139 as of the 2020 census, making it the fifth-most populous city in the United States and the most populous state capital. The Phoenix metropolitan area is estimated to have 5.19 million residents, ranking as the tenth-most populous in the nation. The region's gross domestic product reached over $362 billion by 2022. With an average annual population growth rate of four percent from the mid-1960s to the mid-2000s, Phoenix continues to expand its economic and demographic influence.