The Grotto is Nice
The Grotto is a wonderful, drippy overhanging grotto type alcove, back away from the road at the Grotto shuttle stop. The Grotto itself is a very nice place to hang out on a hot Zion afternoon. The canyon leading to the Grotto - not so much.
Grotto Canyon descends between the Great White Throne and Red Arch Mountain ending at The Grotto. It is not a very appealing canyon. Since it gets very little water flow, it is more like a fault-following gully than a canyon. I did it, so you don't have to.
The road used to end at The Grotto, and is the site of the first ranger cabin and the first park campground. If you are camping in South Campground and wonder where the North Campground might be, think The Grotto.
Spring, summer, or fall
Navigation, anchor skills appropriate to a rarely-visited canyon. Anchors are mostly trees with the occasional manky bolt anchor.
Helmets, rappelling gear, webbing and rapid links.
COLD WATER PROTECTION
None. Bring Plenty.
FLASH FLOOD RISK
Starts on Deertrap Mountain Trail and ends at the Grotto Trailhead. Can either be done as a loop, hiking up from Weeping Rock, or with a shuttle service or car spot starting at the Stave Spring trailhead off the Zion Ponderosa Ranch.
Follow the Deertrap Mountain Trail to near the head of the canyon. You can access the trail from a number of places. If you have two cars, or a shuttle service, you can take the East Rim trail to Deertrap, without too much elevation gain. You could also hike up from Weeping Rock Trailhead to the East Rim trail and the Deertrap Mountain Trail.
Cross the mesa top, then downclimb into the canyon near its head. Downclimb until forced to rappel. A handful of rappels lead to a big drop. Follow ledges out right, then rappel 260 feet (80m) to the canyon bottom. Eventually, rappel about 100 feet (30m) over the dripping overhang of The Grotto. Walk out the little stream to the bus stop.
Follow the small stream to the bus stop at the Grotto Trailhead.