Liebre Summit is the highest point, at 4,213 feet, on the Old Ridge Route. From the route’s origin in Castaic to the south, travelers climb 3,100 feet in 26 miles to reach this point, often wearing out their tires or overheating their cars in the process. For travelers approaching from the Grapevine to the north, reaching the summit requires a climb of 2,400 feet in 22 miles.