The Agua Dulce Mountains are a mountain range in the north-central

Sonoran Desert The Sonoran Desert () is a hot desert and ecoregion in North America that covers the northwestern Mexican states of Sonora, Baja California, and Baja California Sur, as well as part of the Southwestern United States (in Arizona and California). It ...

of southwestern

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

. The range is located in the extreme southwestern portion of

Pima County, Arizona Pima County ( ) is a County (United States), county in the south central region of the U.S. state of Arizona, one of 15 List of counties in Arizona, counties in the state. As of the 2020 United States census, 2020 census, the population was 1 ...

, immediately north of the international boundary with

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

and about southwest of

Ajo, Arizona Ajo ( ) is an Unincorporated area#United States, unincorporated community in Pima County, Arizona, United States. It is the closest community to Organ Pipe Cactus National Monument. The population was 3,039 at the 2020 United States census, ...

. The range has three main sections that total about 15 miles in length and about nine miles in width. The range is located entirely within the

Cabeza Prieta National Wildlife Refuge Cabeza Prieta National Wildlife Refuge (CPNWR) is located in southwestern Arizona in the United States, along of the Mexico–United States border. It is bordered to the north and to the west by the Barry M. Goldwater Air Force Range, to the ...

. The highpoint of the range is above sea level and is located at 32°01'32"N, 113°08'44"W (NAD 1983 datum). The summit is unnamed, but is marked on

U.S. Geological Survey The United States Geological Survey (USGS), founded as the Geological Survey, is an agency of the U.S. Department of the Interior whose work spans the disciplines of biology, geography, geology, and hydrology. The agency was founded on March ...

(USGS) maps for the "Quitovaquita" benchmark that was placed on the summit in 1920. The original surveyed height was 2,850 feet above sea level, but recent datum adjustments calculate the summit to be two feet higher. The name of the range has been in use for at least 100 years, though it has been called the "Sierra del Ojo" and the "Sonoyta Mountains" on some older maps. A map created by the

U.S. Army Corps of Engineers The United States Army Corps of Engineers (USACE) is the military engineering branch of the United States Army. A direct reporting unit (DRU), it has three primary mission areas: Engineer Regiment, military construction, and civil wor ...

around 1920 labeled the range the "Quitovaquita Mountains." This is in reference to

Quitobaquito Springs Quitobaquito Springs are springs in Organ Pipe Cactus National Monument in Pima County, Arizona. The name is of Tohono O'odham origin meaning 'house ring spring'. The area has been populated for at least 16,000 years. It lies at an elevation of ...

, which lie approximately nine miles southeast of the range in what are now called the

Quitobaquito Hills Quitobaquito Hills is a range of hills in Pima County, Arizona. The name is of Tohono O'odham - Spanish origin meaning 'house ring spring'. Its tallest summit is an unnamed hill that overlooks Cipriano Pass to the east. The range trends northwe ...

. The Quitobaquito Hills, however, do not share a connection with the Agua Dulce Mountains. "Agua Dulce" means "sweet water" in Spanish and refers to pools of non-saline water on the

Sonoyta River The Sonoyta River is a river of Sonora, Mexico. It is part of the Gulf of Calilfornia watershed. See also * List of longest rivers of Mexico * List of rivers of Mexico This is a list of rivers of Mexico, listed from north to south. There are ...

several miles to the south in Mexico. These pools are in contrast to "Agua Salada," which is located further downstream on the river and yields only highly mineralized and brackish water. The range also contains a small spring on its southern slope that also bears the name Agua Dulce, though it is likely that the range is named for the pools on the river rather than the spring, since the pools played prominently in the history of the area whereas the spring is small and well away from the historical Sonoyta River travel corridor. The range is home to a number of abandoned mines, most notably the Papago Mine and the Legal Tender Mine, which were worked in the late 19th and early 20th centuries. Papago Well was drilled nearby during the same period to provide water to the mines.Bryan, Kirk. 1925. The Papago Country, Arizona: A Geographic, Geologic, and Hydrologic Reconnaissance with a Guide to Desert Watering Places. Water Supply Paper No. 499. United States Geological Survey. Washington, D.C. Later the well was used to provide water to cattle that grazed in the area, and now the windmill pumps water to a guzzler for wildlife. The Davidson Canyon area and the associated bajada to the south of the range contain the northernmost populations of senita cactus (''

Pachycereus ''Pachycereus'' is a genus of large cacti native to Central America and Mexico. They form large shrubs or small trees up to 15 m tall, with stout stems up to 1 m in diameter. ''Pachycereus'' comes from the ancient Greek παχύς (''p ...

schottii''). This columnar cactus is very common further south in Mexico, but in the United States it is restricted to small areas of

Organ Pipe Cactus National Monument Organ Pipe Cactus National Monument is a U.S. national monument and UNESCO biosphere reserve located in extreme southern Arizona that shares a border with the Mexican state of Sonora. The park is the only place in the United States where the ...

and this isolated population in the Cabeza Prieta National Wildlife Refuge.

References

{{Mountains of Arizona Mountain ranges of Arizona Mountain ranges of Pima County, Arizona Mountain ranges of the Sonoran Desert Sonoran Desert