As of the census of 2000, there were 3,705 people, 1,659 households, and 1,088 families residing in the CDP. The population density was 132.0 people per square mile (51.0/km). There were 2,485 housing units at an average density of 88.5 per square mile (34.2/km). The racial makeup of the CDP was 78.70% White, 0.24% Black or African American, 6.88% Native American, 0.30% Asian, 0.08% Pacific Islander, 9.15% from other races, and 4.64% from two or more races. 37.57% of the population were Hispanic or Latino of any race.
There were 1,659 households out of which 19.7% had children under the age of 18 living with them, 51.4% were married couples living together, 10.6% had a female householder with no husband present, and 34.4% were non-families. 30.1% of all households were made up of individuals and 17.1% had someone living alone who was 65 years of age or older. The average household size was 2.23 and the average family size was 2.74.
In the CDP the population was spread out with 20.6% under the age of 18, 4.9% from 18 to 24, 17.2% from 25 to 44, 25.3% from 45 to 64, and 32.1% who were 65 years of age or older. The median age was 52 years. For every 100 females there were 90.3 males. For every 100 females age 18 and over, there were 88.3 males.
The median income for a household in the CDP was $25,618, and the median income for a family was $29,310. Males had a median income of $28,000 versus $18,571 for females. The per capita income for the CDP was $14,548. About 16.5% of families and 22.3% of the population were below the poverty line, including 36.5% of those under age 18 and 9.0% of those age 65 or over.
Ajo Unified School District is the only regular school district in Ajo, Arizona. However, the CDP is in Pima County Joint Technical Education Districts 3rd Governing Board District. There is currently a First Things First prekindergarten program, an elementary school, a middle school, a high school, and a Head Start Program, all of which are located on the same campus. The high school currently has a gridiron football team, a volleyball team, a basketball team (both boys and girls), a baseball team (boys), a softball team (girls), a golf team, and track & field. They are known as the Ajo Red Raiders.