Pima County ( ) is a county in the south central region of the U.S. state of Arizona. As of the 2020 census, the population was 1,043,433, making it Arizona's second-most populous county. The county seat is Tucson, where most of the population is centered. The county is named after the Pima Native Americans, also known as Tohono O'odham, who are indigenous to this area.
Pima County includes the entirety of the Tucson Metropolitan Statistical Area, and it is the third largest metropolitan area in the Southwestern United States.
Pima County contains parts of the Tohono O'odham Nation, as well as all of the San Xavier Indian Reservation, the Pascua Yaqui Indian Reservation, Organ Pipe Cactus National Monument, Ironwood Forest National Monument and Saguaro National Park.
The vast majority of the county population lies in and around the city of Tucson (2021 city population: 543,242), filling much of the eastern part of the county with urban development. As Arizona's second-largest city, Tucson is a major commercial and academic center. Other urban areas include the Tucson suburbs of Marana (population 44,792), Oro Valley (population 44,350), Sahuarita (population 29,318), and South Tucson (population 5,643), a large ring of unincorporated urban development, and the growing satellite town Green Valley. The rest of the county is sparsely populated; the largest towns are Sells, the capital of the Tohono O'odham Nation, and Ajo in the county's far western region.
History
Pima County, one of the four original counties in Arizona, was created by the 1st Arizona Territorial Legislature with land acquired through the Gadsden Purchase from Mexico in 1853. The original county consisted of all of Arizona Territory east of longitude 113° 20' and south of the Gila River. Soon thereafter, the counties of Cochise, Graham and Santa Cruz were carved from the original Pima County.
Geography
According to the United States Census Bureau, the county has a total area of , of which is land and (0.02%) is water.
Topographic features
Mountains of Pima County
Fresnal Canyon
Major highways
Interstate 10
Interstate 19
Historic U.S. Route 80
State Route 77
State Route 83
State Route 85
State Route 86
State Route 210
State Route 989
Adjacent counties and municipalities
Yuma County – west
Maricopa County – north
Pinal County – north
Graham County – northeast
Cochise County – east
Santa Cruz County – southeast east and south
Altar, Sonora, Mexico – south
Caborca, Sonora, Mexico – south
General Plutarco Elías Calles, Sonora, Mexico – south
Sáric, Sonora, Mexico – south
National protected areas
Buenos Aires National Wildlife Refuge
Cabeza Prieta National Wildlife Refuge (part) Coronado National Forest (part) Ironwood Forest National Monument (part) Las Cienegas National Conservation Area (part) Organ Pipe Cactus National Monument Saguaro National Park
Sonoran Desert Conservation Plan
The Sonoran Desert Conservation Plan (SDCP) is Pima County's plan for desert conservation. The SDCP addresses natural and cultural resources, ranches, endangered species compliance and wildlife corridors.
Demographics
2000 census
As of the census of 2000, there were 843,746 people, 332,350 households, and 212,039 families living in the county. The population density was . There were 366,737 housing units at an average density of . The racial makeup of the county was 75.1% White, 3.0% Black or African American, 3.2% Native American, 2.0% Asian, 0.1% Pacific Islander, 13.3% from other races, and 3.2% from two or more races. 29.3% of the population were Hispanic or Latino of any race. 22.8% reported speaking Spanish at home.
There were 332,350 households, out of which 29.2% had children under the age of 18 living with them, 47.7% were married couples living together, 11.8% had a female householder with no husband present, and 36.2% were non-families. 28.5% of all households were made up of individuals, and 9.4% had someone living alone who was 65 years of age or older. The average household size was 2.47 and the average family size was 3.06.
In the county, the population was spread out, with 24.6% under the age of 18, 10.9% from 18 to 24, 28.4% from 25 to 44, 21.9% from 45 to 64, and 14.2% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 95.7 males. For every 100 females age 18 and over, there were 92.7 males.