Maricopa County is 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.

Joseph Michael Arpaio is an American former law enforcement officer and politician. He was the Sheriff of Maricopa County, Arizona for 24 years, from 1993 to 2017, losing reelection to Democrat Paul Penzone in 2016.