At 2,969,602 acres, Tonto is by some distance the largest of the six national forests in Arizona, and has the most interesting, diverse scenery, with terrain and elevation ranging from the Sonoran Desert (1,400 feet) to the Mogollon Rim (7,400 feet). Besides desert and mountains it contains lakes - mostly artificially created, fertile river valleys, rocky canyons and flat plains. Much of the lower elevations are covered by cacti, in particular the familiar giant saguaro, but there are also dozens of smaller species. The cactus colonies merge with bushes, chaparral and grasslands above 4,000 feet, while the higher hills to Pleasant Valley and the north support varied woodland habitats including juniper, mixed fir and ponderosa pine.

Tonto contains eight separate wilderness areas, all of which have quite limited access as the land is generally steep and rough, without many trails, and experiences harsh weather for most of the year. The Pleasant Valley Ranger District is located on all four sides of the town of Young, and it continues north to the Mogollon Rim and east to the Fort Apache Indian Reservation. The District consists of approximately 420,000 acres (approx. 170,000 hectares) of Chaparral, Piñyon-Juniper, as well as significant areas of scattered Ponderosa Pine-Junipers types.