According to data from the 2010 U.S. Census, Maricopa, Pima and Pinal are the three most populous Arizona counties. Maricopa County reportedly had 3.8 million residents, while Pima and Pinal counties had 980,000 and 376,000, respectively.Continue Reading
The 3.8 million residents in Maricopa County represents a 25-percent increase from that county's 2000 population. Pima County saw a 16-percent increase in population since 2000, and Pinal County more than doubled its population with a 109-percent increase.
Other large counties in Arizona include Yavapai, with a population of 211,000; Mohave, with a population of 200,000; and Yuma, with a population of 196,000, as of 2010. The population of each of the three counties increased between 20 and 30 percent over the 10-year period since 2000.Learn more about The West