How much of the Great Wall’s route consists of natural barriers such as rivers and mountain ridges?

Approximately one-fourth of the Great Wall of China’s total length consists of natural barriers, such as mountain ridges and rivers. The remaining portion of the route—about 70 percent—is comprised of actual constructed wall, while the small remaining stretches consist of ditches or moats.1

As the wall snakes across the Chinese countryside, it frequently traces the crestlines of hills and mountains to utilize the natural terrain for defense. In some areas, builders incorporated existing river dikes or rugged features like cliffs and gorges to serve as substitutes for man-made structures.12