9. Palo Duro Canyon – Texas
Palo Duro Canyon is a canyon system of the Caprock Escarpment located in the Texas Panhandle south of Amarillo. It is the second-largest canyon in the United States, roughly 70 miles long and has an average width of 6 miles (but reaches a width of 20 miles at places). Its depth is around 820 feet, but is about 1,000 feet in a few places. The canyon provides hikers and those who enjoy the outdoors with plenty of nature trails and photographers will love the geological features including the Lighthouse Peak.