Pima County is located in the south central region of the U.S. state of Arizona. The county is named after the Pima American Indian tribe which was indigenous to the area. Pima County, the second largest of the four original Arizona counties, and was created in 1864.

The county seat is Tucson, where the vast majority of the county population lies in and around. Tucson has grown to be the second largest city in Arizona. It has always served as the Pima County seat and was the Arizona Territorial capital from 1867 to 1877.

Tucson is home to the University of Arizona and many historical and cultural attractions. Within Pima County are two cactus forests, Saguaro National Monument to the north and Organ Pipe Cactus National Monument in the western portion.