The Gatekeeper, Rejuvenation Tree, or General Norton, Big Stump Grove:

This tree is 17.3 feet in diameter level at the high side ground, 17.4 feet in diameter at chest height, and 144 feet tall.  It is badly damaged at the top and though you would not know it from a distance its hollow all the way up through its center.  It is located right at the west entrance to kings canyon, stop sometime and walk around to its back side where you can look up and see the sky thru its hole.