The Madrean Sky Islands are enclaves of Madrean pine–oak woodlands, found at higher elevations in a complex of small mountain ranges in southern and southeastern Arizona, southwestern New Mexico, and northwestern Mexico.

The sky islands were isolated from one another and from the pine–oak woodlands of the Sierra Madre Occidental to the south by the warming and drying of the climate since the ice ages.

There are approximately 27 Madrean sky islands in the United States, and 15 in northern Mexico.

Significant urban areas located very close to the Madrean Sky Islands include Las Cruces, New Mexico, and Tucson, Arizona.

Though formerly extirpated from the United States, the North American jaguar has returned to the area from northern Mexico in small numbers.