Maricopa County, Arizona

Maricopa County
The Maricopa County Courthouse and Old Phoenix City Hall, also known as the County-City Administration Building, in 2013
Location within the U.S. state of Arizona
Arizona's location within the U.S.
Coordinates: 33°30′50″N 112°28′33″W / 33.5139°N 112.4758°W / 33.5139; -112.4758
Country United States
State Arizona
FoundedFebruary 14, 1871
Named afterMaricopa people
SeatPhoenix
Largest cityPhoenix
Area
  Total
9,224 sq mi (23,890 km2)
  Land9,200 sq mi (24,000 km2)
  Water24 sq mi (60 km2)  0.3%
Population
 (2020)
  Total
4,420,568
  Estimate 
(2024)
4,673,096
  Density480/sq mi (190/km2)
Time zoneUTC−7 (Mountain)
Congressional districts1st, 2nd, 3rd, 4th, 5th, 7th, 8th, 9th
Websitewww.maricopa.gov

Maricopa County (/ˌmærɪˈkpə/) is a county in the south-central part of the U.S. state of Arizona. As of the 2020 census the population was 4,420,568, or about 62% of the state's total, making it the fourth-most populous county in the United States and the most populous county in Arizona, and making Arizona one of the nation's most centralized states. The county seat is Phoenix, the state capital and fifth-most populous city in the United States.

Maricopa County is the central county of the Phoenix–Mesa–Chandler Metropolitan Statistical Area. The Office of Management and Budget renamed the metropolitan area in September 2018. Previously, it was the Phoenix–Mesa–Glendale metropolitan area, and in 2000, that was changed to Phoenix–Mesa–Scottsdale.

Maricopa County was named after the Maricopa people. Five Indian reservations are located in the county. The largest are the Salt River Pima–Maricopa Indian Community (east of Scottsdale) and the Gila River Indian Community (south of Chandler).