Pinal County is located in the central part of the U.S. state of Arizona. As of the 2010 census, its population was 375,770. The county seat is Florence.
Pinal County contains parts of the Tohono O'odham Nation, the Gila River Indian Community and the San Carlos Apache Indian Reservation, as well as the entirety of the Ak-Chin Indian Community.
Because Pinal County is located between Arizona's two largest metropolitan regions, Phoenix and Tucson, suburban growth southward from greater Phoenix has begun to spread into the northern parts of the county; similarly, growth northward from Tucson is spreading into the southern portions of the county. The Pinal County cities of Maricopa and Casa Grande, as well as many unincorporated areas, have shown accelerated growth patterns in recent years; such suburban development is likely to continue for the foreseeable future.