Stonewall Peak is a prominent mountain in San Diego County, California, located in Cuyamaca Rancho State Park. It is east of San Diego and south of Julian.

The summit is accessible from Paso Picacho Campground, which is accessed by California State Route 79. Hikes can be done as an out and back going up the west side of the mountain, which is about four miles round trip, or it can be a loop, going up the west side and down the north, for a total of just over five miles.

Stonewall Peak was named after Stonewall Mine which was between Stonewall Peak and Lake Cuyamaca. The mine was originally named Stonewall Jackson Mine, after Confederate general Stonewall Jackson, and was founded in 1870. The mine was one of the richest in all of San Diego. Anti-Southern sentiments eventually led to the name being shortened to Stonewall Mine.

The peak's original Kumeyaay name was Cushi-Pi, meaning "Sharp Peak". There are efforts to change the peak's official name to this.