Skip to main content

U.S. Forest Service

What are Sky Islands?

Sky Islands are isolated mountain ranges in southeastern Arizona and northern Mexico. Some of the mountains rise more than 6,000 feet above the surrounding desert floor making the lowlands and high peaks drastically different. Plants and animals living in the mountains could never survive in the surrounding deserts. Thus by analogy, the mountains are “islands” surrounded by deserts that are “seas”.

The Sky Islands connect two very different mountainous regions, the subtropical Sierra Madre of Mexico and the temperate Rocky Mountains of the United States. The mixing of these southern and northern biotas is truly unique.

Sky Islands are places where you can see incredible plant diversity in only a few miles. It is easy to visit both deserts and alpine areas in the same day.

We know the Sky Islands for their unique biodiversity and natural beauty.

Map of the sky island areas. The Sky Islands link temperate mountain ranges in the United States with subtropical mountain ranges in Mexico. Elevations: white = below 5,000 feet, green = 5,000 to 7,250 feet, blue = 7,250 feet or higher. (Map adapted from Gottfried, et al. 2005).

Desert scene displaying dry, rocky, shrubs, and cactuses. Desert scene. Photo by Charlie McDonald.

Mountain alpine scene displaying lush forest meadow and yellow flowers. Mountain alpine scene. Photo by Louis Saint.

Further Reading

Next: Climate Changes and Evolving Plants…