Mount Graham (called in Nnee biyati' (Western Apache) Dził Nchaa Sí'an – 'Big Seated Mountain') is a mountain in Graham County, Arizona, United States, approximately 70 miles (110 km) northeast of Tucson.

[6] Mount Graham summits are headwaters for numerous perennial streams that tumble through five major botanical zones.

Located between the southern Rocky Mountains and Mexico's Sierra Madre Occidental, and biologically isolated for millennia, the higher elevations have provided refuge for relict populations of plants and animals with adaptive strategies rooted in Pleistocene ice age environmental conditions.

Of particular note are stands of the oldest conifer trees in the U.S. Southwest and associated habitats for threatened and endangered species, especially the Mount Graham Red Squirrel.

[11] The United States Congress authorized construction of the observatories on the mountain in 1988, but there has been outcry from the four federally recognized tribes of the Western Apache Nation and Native American groups, who consider the site to be sacred.