Trinity Canyon — One of the smaller drainages on the north side, Trinity is larger than most canyons on the south side, and more complex. Very hard structures of Vishnu in this area make Trinity narrow, winding, and impassable. Trinity is a well-known pothole water source (west fork granite tanks) and may have a good flow of water here in the winter or spring, but it can be dry and is not considered a reliable water source, and there is no river access from the upper bed.

Routes — Part of the Crystal/Phantom Loop in GCLH-I. The quickest access from Bright Angel (no kidding) is by Utah Flats to Cheops/Isis saddle, and along the southern flank of Isis Temple. There are a couple of other ways that would seem shorter, but not. The eastside access into the east fork is a break formed by a fault alignment across this drainage directly west of the divide to Ninetyone Mile. The west access is under a small hill on the Tapeats slope up from where the two forks join; the northern side of this slope is unusually steep but also clearly much-used.

Continuing up Trinity and following the east fork will lead to a walkup through the Redwall above Phantom Creek, and then on to Shiva saddle and the rim.

Downriver to Ninetyfour Mile Canyon. The nearby accesses are to upper Phantom Creek going over the Cheops/Isis saddle, or over the divide into the basin above Ninetyone Mile Canyon; both of these locations are access to water from here if that is a problem.

1996 December - First exploration with Danny, coming from Ninetyone Mile Canyon, going out to the point upriver (Steck’s "emergency water route" looks scary). We then followed the Quartzite terrace along the base of Isis into Phantom Creek (good, fast track). Many antlers on the mesa; 6 deer spotted. Cave with lion mound along descent ravine into east fork (easy travel).

2004 November - From Shinumo, a late lunch stop with ample water supply in the granite upstream on the west fork. Then on to Camp 8 at the divide above Ninetyone Mile. Next day, continuing across the Cheops/Isis saddle heading for Utah Flats.