Series: Defining the Southwest

The Transition Highlands, or Central Mountains, consist of numerous rugged low mountains marking the boundary between the tablelands of the Colorado Plateau and the southern deserts of the Basin and Range physiographic zone.

In the Southwest, the Transition Highlands are dominated by the Mogollon Rim, a massive break in the earth’s topography stretching diagonally across Arizona and into New Mexico. In places, the Rim is a sheer escarpment nearly 2,000 feet high.

Looking out at a highland landscape covered in ponderosa pine forest from within a cliff dwelling
The transitional highlands as viewed from a cliff dwelling at Gila Cliff Dwellings National Monument.

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Area: 33,735 sq. miles.

Precipitation: Average 25- 51 cm (10-12 in); above 1,524 meters (5,000 ft) in elevation, much of the annual precipitation in the Transitional zone falls as snow. On the Mogollon Rim, precipitation averages 50 cm (21 in).

Snow blanketing highlands, viewed from an area free of snow.
Much of the annual precipitation in the Transitional zone falls as snow. Here, a recent snowfall is viewed from Tonto National Monument.

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Temperature: Temperatures in the Transition Highlands are relatively moderate; summer temperatures reach the low 90s and winter temperatures drop into the mid-20s.

Elevation: The elevation of the Transition Zone averages between 1,200 – 1,500 meters (4,000 – 5,000 feet), but exceeds 2,130 meters (7,000 ft) along the Mogollon Rim.

Life Zones: Upper Sonoran

Vegetation: Open ponderosa pine forests dominate much of the Transition Zone, but oak woodlands, chapparal, oak-pine woodlands, and pinyon-juniper woodlands also form the vegetative regimes of the region.

A vibrant green forest covers a ridge and canyon landscape
Ponderosa pine forests dominate much of the Transition Zone.

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Geology: The geology of the Transition Zone includes sedimentary, igneous, and metamorphic rocks. The geological conditions of the region have resulted in extensive deposits of copper, which is mined around Clifton and Globe.

Prehistoric Cultures: Mogollon, Salado, Mimbres Mogollon, and Southern Sinagua.

The outer walls and windows of a dwelling nestled into the face of  sheer cliff
The Sinagua people who left behind the cliff dwellings seen at Montezuma Castle National Monument, are among the prehistoric peoples who occupied the Transition Highlands.

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National Parks and Monuments: Tuzigoot, Montezuma’s Castle, Tonto, and Gila Cliff Dwellings.