The Kennecott Mining Company had Kearny built in 1958 to accommodate the residents of the nearby towns of Barcelona, Ray and Sonora, which towns were about to be under-mined and swallowed whole by expansion at Kennecott's open pit copper mine. Some of the mine employees had their homes moved into Kearny but most construction in town was brand new at the time. The mine is now owned and operated by ASARCO (the American Smelting and Refining Company).

Kearny was named in honor of General Stephen Watts Kearny who traveled through the area on November 7, 1846 on his way to California during the Mexican-American War. Kearny declared the area "hostile and uninhabitable," which was kinda funny because Apaches had lived in this area for hundreds of years before the European invaders arrived. But for Kearny and the 100 dragoons traveling with him, the going was so hard that he sent word back to the Mormon Battalion that they should travel further south and make their way to California through the Mexican pueblo of Tucson.

The area has a long and colorful history in regards to the gold and silver prospectors, and the outlaws and scam artists that came with them. But copper was discovered in the area of Ray and underground mining of that started around 1905. The underground mining gave way to an open pit method in 1947 and that pit is still getting bigger and deeper today.

ASARCO copper mine near Kearny, Arizona
The ASARCO open pit copper mine, Teapot Peak in the distance