The Tonto National Forest, encompassing 2,873,200 acres, is the largest of the six national forests in Arizona and is the ninth largest national forest in the United States. The forest has diverse scenery, with elevations ranging from 1,400 feet in the Sonoran Desert to 7,400 feet in the ponderosa pine forests of the Mogollon Rim. The Tonto National For…The Tonto National Forest, encompassing 2,873,200 acres, is the largest of the six national forests in Arizona and is the ninth largest national forest in the United States. The forest has diverse scenery, with elevations ranging from 1,400 feet in the Sonoran Desert to 7,400 feet in the ponderosa pine forests of the Mogollon Rim. The Tonto National Forest is also one of the most visited "urban" forests in the United States.