Pima County is a county 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. The population was 843,746 at the 2000 census. The county seat is Tucson, where nearly all of the population is centered.

Pima County contains parts of the Tohono O'odham Nation, as well as all of the San Xavier Indian Reservation, Organ Pipe Cactus National Monument, Ironwood Forest National Monument and Saguaro National Park.

Tucson, Arizona's second largest city, is a major commercial and academic center. Other urban areas include the Tucson suburbs of Oro Valley (population 39,400), Marana ( population 26,725 ), Sahuarita (population 13,990), and South Tucson ( population 5,630 ), a large ring of unincorporated urban development, and the growing satellite town Green Valley. ty.