Giant Rock is a large freestanding boulder in the Mojave Desert near Landers, California, and the Marine Corps Air Ground Combat Center Twentynine Palms. The boulder covers 5,800 square feet of ground and is seven stories high. Giant Rock is the largest freestanding boulder in North America and is purported to be the largest free standing boulder in th…Giant Rock is a large freestanding boulder in the Mojave Desert near Landers, California, and the Marine Corps Air Ground Combat Center Twentynine Palms. The boulder covers 5,800 square feet of ground and is seven stories high. Giant Rock is the largest freestanding boulder in North America and is purported to be the largest free standing boulder in the world.