Arizona's County Population as a Share of the State, 2010
Of Arizona’s nearly 6.4 million residents on April 1, 2010, approximately 60 percent—more than 3.8 million—lived in Maricopa County, in which most of the Phoenix metropolitan area is located. Another 6 percent of the state’s residents lived in Pinal County, which also is part of the Phoenix metro area. Pima County (the Tucson metro area) had nearly 1 million residents (15 percent of the state total). Combined, Arizona’s 12 counties outside of the Phoenix and Tucson metro areas were home to a little more than 1.2 million residents (19 percent of the state total) in 2010.