Is the Grand Canyon largest canyon in US?

The Grand Canyon is not the largest canyon in the US. The largest canyon in the US is the Hells Canyon, located on the border between Idaho and Oregon. Hells Canyon is 10,500 feet (3,200 m) deep and 55 miles (88 km) long. The Grand Canyon is 1,800 feet (550 m) deep and 277 miles (446 km) long.