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.
The vast majority of the county population lies in and around the city of Tucson (2005 city population: 529,770), filling much of the eastern part of the county with urban development. 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. 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 far western region of the county.
2000 843,746 1990 666,880 1980 531,443 1970 351,667 1960 265,660 1950 141,216 1940 72,838 1930 55,676 1920 34,680 1910 22,818 1900 14,689 1890 12,673 1880 17,006 1870 5,716
As of the census of 2000, there were 843,746 people, 332,350 households, and 212,039 families residing in the county. The population density was 92 people per square mile (35/km²). There were 366,737 housing units at an average density of 40 per square mile (15/km²). The racial makeup of the county was 75.07% White, 3.03% Black or African American, 3.22% Native American, 2.04% Asian, 0.13% Pacific Islander, 13.30% from other races, and 3.21% from two or more races. 29.34% of the population were Hispanic or Latino of any race. 22.80% reported speaking Spanish at home [1].
There were 332,350 households out of which 29.20% had children under the age of 18 living with them, 47.70% were married couples living together, 11.80% had a female householder with no husband present, and 36.20% were non-families. 28.50% of all households were made up of individuals and 9.40% 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 24.60% under the age of 18, 10.90% from 18 to 24, 28.40% from 25 to 44, 21.90% from 45 to 64, and 14.20% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 95.70 males. For every 100 females age 18 and over, there were 92.70 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 10.50% of families and 14.70% of the population were below the poverty line, including 19.40% of those under age 18 and 8.20% of those age 65 or over.