The Gila Bend Mountains are in southwest Maricopa County, Arizona. Located 65 miles west-southwest of Phoenix. The Gila River makes a 90 degree turn on it's way towards the mighty Colorado River and these mountains border the northwest of this bend. The town of Gila Bend is southeast of the mountains. They are rocky and rugged; spanning 35 miles, with Woosley Peak being the highest elevation at 3,170 feet.
The geology of the Gila Bend Mountains is extremely complex ranging in age from Pre-Tertiary Units to Middle Tertiary. The Pre-Tertiary Units consist of granodiorite, diorite, diabase dikes, gneiss, schist, and minor quartzite and minor felsic crystalline rocks. Most of the Middle Tertiary in our area of interest are volcanics. Volcanics here range from dark basalts to brown and gray andesite, locally flow banded. Sandstone, siltstone, shale, and conglomerate make up the balance of the Middle Tertiary Units. Copper in the form of chrysocolla, cuprite, bornite, malachite and chalcocite with minor amounts of gold, silver, uranium, and barite are found in several of the larger workings. Copper oxides are exposed in outcrops and in numerous small pits and trenches over a large area.
The Buckeye Copper, Hargan and Idazona Mines are all in the Gila Bend Mountains and produced primarily copper with gold and silver often being secondary. The Southern Pacific Railroad’s arrival to Gila Bend in 1879 helped the area’s copper mining industry. Arizona’s state flag bears a copper star to represent its position as the largest copper producing state in the United States.