What canyon in the u.s. is second to the grand canyon in depth?

Question

What canyon in the u.s. is second to the grand canyon in depth?

Answer 1

The Salmon River cuts the second-deepest canyon in North America. It's in Idaho and about a mile deep.

Answer 2

Devils Canyon, in between Oregon and Idaho. Actually, I heard there is a section of it that is deeper than any section of the Grand Canyon, but I don't know that for sure.  

Answer 3

h***s canyon between Oregon and Idaho is the deepest canyon in the US, but is less famous because the scenery isn't as impressive.

The Grand canyon is second behind h**l's Canyon in depth