Mark Lamb is an American law enforcement officer and politician who has served as the sheriff of Pinal County, Arizona, since 2017. As a member of the Republican Party, Lamb previously served in the Salt River Pima–Maricopa Indian Community police department.

Pinal County is in the central part of the U.S. state of Arizona. According to the 2020 census, the population of the county was 425,264, making it Arizona's third-most populous county. The county seat is Florence. The county was founded in 1875.