Blood, Trauma, and Biohazard Cleanup in Ajo, AZ

Ajo is an unincorporated community and census-designated place in Pima County, Arizona, set in the Little Ajo Mountains of the Sonoran Desert.

The 2020 Census counted 3,039 residents in Ajo, down from 3,304 in 2010.

The 2020 Census counted 1,472 households in Ajo, and more than a third of its residents, 36.6 percent, were aged 65 or older, giving the community a median age of 55.9 years.

Ajo is the closest community to Organ Pipe Cactus National Monument and lies on State Route 85 about 43 miles north of the Mexican border.

Its name is the Spanish word for garlic, and it may come from the similar-sounding O'odham word for paint, because the Tohono O'odham obtained red paint pigments in the area.

Spanish miners worked a mine near Ajo known as the Old Bat Hole in the early 1800s before abandoning it; Tom Childs Sr. rediscovered it in 1847, and the main copper claims were located in 1884.

Ajo's rich native copper made it the site of the first copper mine in Arizona, and in the 1880s its ore was shipped around Cape Horn to be smelted in Swansea, Wales.

Colonel John Campbell Greenway bought the New Cornelia mine in 1911 and developed Ajo into a company mining town; Phelps Dodge acquired the mine in 1921 and employed more than 1,000 people at its open pit.

Copper production at Ajo ended in 1985 after a 1983 strike, and the Tucson, Cornelia and Gila Bend Railroad, which had served the town since 1916, also ceased operating that year.

Ajo peaked at 7,049 residents in 1960, when it was the second-largest community in Pima County after Tucson, and it was designated a census-designated place in 1980.