The vast majority of the county population lies in and around the city of Tucson, 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, Oro Valley, Sahuarita, South Tucson, and 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.
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.[3] Soon thereafter, the counties of Cochise, Graham and Santa Cruz were carved from the original Pima County.[4]
According to the United States Census Bureau, the county has a total area of 9,189 square miles (23,800 km2), of which 9,187 square miles (23,790 km2) is land and 2.1 square miles (5.4 km2) (0.02%) is water.[5]
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.[6]
As of the census of 2010, there were 980,263 people, 388,660 households, and 243,167 families living in the county.[12] The population density was 106.7 inhabitants per square mile (41.2 inhabitants/km2). There were 440,909 housing units at an average density of 48.0 units per square mile (18.5 units/km2).[13] The racial makeup of the county was 74.3% white, 3.5% black or African American, 3.3% American Indian, 2.6% Asian, 0.2% Pacific islander, 12.3% from other races, and 3.7% from two or more races. Those of Hispanic or Latino origin made up 34.6% of the population.[12]
Of the 388,660 households, 29.8% had children under the age of 18 living with them, 44.5% were married couples living together, 12.8% had a female householder with no husband present, 37.4% were non-families, and 29.2% of all households were made up of individuals. The average household size was 2.46 and the average family size was 3.06. The median age was 37.7 years.[12]
The median income for a household in the county was $45,521 and the median income for a family was $57,377. Males had a median income of $42,313 versus $33,487 for females. The per capita income for the county was $25,093. About 11.2% of families and 16.4% of the population were below the poverty line, including 22.6% of those under age 18 and 8.5% of those age 65 or over.[15]
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 92 people per square mile (36 people/km2). There were 366,737 housing units at an average density of 40 units per square mile (15 units/km2). 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.[16]
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.
The median income for a household in the county was $36,758, and the median income for a family was $44,446. Males had a median income of $32,156 versus $24,959 for females. The per capita income for the county was $19,785. About 10.5% of families and 14.7% of the population were below the poverty line, including 19.4% of those under age 18 and 8.2% of those age 65 or over.
Pima County is governed by a five-member Board of Supervisors who set ordinances and run services for the areas that do not fall within any city or town's jurisdiction.
In Arizona, counties are creatures of the state, and do not have charters of their own. The county Board of Supervisors acts under powers delegated by state law, mainly related to minor ordinances and revenue collection. With few exceptions, these powers are narrowly construed. The state legislature devotes considerable time to local matters, with legislative approval required for many of the most basic local issues.
The Pima County Board of Supervisors is responsible for steering public policy in the region. The five-member board provides direction to the County Administrator, Jan Lesher,[20] and the county's various departments as they work to ensure safe communities, nurture economic development, sustainably manage natural resources and protect public health. In addition to overseeing the delivery of a host of municipal services, from roads to parks and libraries and law enforcement, board members also are responsible for approving the county budget. Elected to four-year terms, board members also set the amount of taxes to be levied.
The Pima County Sheriff's Department provides court protection, administers the county jail, provides coroner service, and patrols the unincorporated parts of Pima County. It is the seventh largest sheriff's department in the nation.[29] Incorporated towns within the county with municipal police departments are Tucson, Marana, Oro Valley, and Sahuarita.
Being home to a major population center and a major research university, Pima County is one of the most reliably Democratic counties in Arizona. After voting Democratic through 1930s and 1940s, it swung Republican following major population increase after World War II, becoming a Republican-leaning county. However, in 1964, it rejected Arizona's native son Barry Goldwater by seven points, who won statewide by one point. However, despite the county's Republican lean, Democrats would not win 40% of the vote only twice - in 1972, when George McGovern lost in a 49-state landslide and due to a balloting error in the county, the Socialist Workers Party came a distant third with 18% of the vote;[30] and in 1980, when Jimmy Carter, being largely insensitive to Western states' issues, also lost many votes to independent John B. Anderson. Following Bill Clinton's plurality victory by 12 points in 1992, all Democrats since 1996 have won the county by a majority and no Republican has come closer than six points in recapturing the county. In both 2016 and 2020, Donald Trump became the first Republican since Bob Dole in 1996 to fail to win 40% of the county's vote. However, Trump won 41.7% of the county's vote in his third presidential run in 2024.
United States presidential election results for Pima County, Arizona[31]
Map of the incorporated and unincorporated cities and towns in Pima County. Also shown are the borders for the Indian Reservations in the county.Astronaut photo of the open-pit copper mines adjacent to Green Valley, 2010. North is to the left.
United States
Arizona
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
Geographic data related to Pima County, Arizona at OpenStreetMap