Known primarily among Marines undergoing training at the School of Infantry at Camp Pendleton, California as the least desirable place to hump a pack. Tops off at "Recon Ridge". Named as such because when you are going up, your thoughts consist of little more than "motherfucker..."
PFC. Smith: Fuuuck, we're doing what for PT today?
PVT. Johnson: A pack run up Mount Motherfucker.