County Seat: Phoenix
Founded: 1871
Area: 9,200 square miles
Population: 3,817,117 (2010)
Other Major Cities: Gila Bend, Mesa, Scottsdale, Wickenburg
Geographic Highlights: Nearly 60 percent of Arizona’s population calls Maricopa County home. In Phoenix, 2,680-foot Camelback Mountain is a popular and strenuous hike. Other attractions include the Four Peaks Wilderness, Bartlett Lake and South Mountain Park.