Northeast of St. George and Springdale in the Zion National Park, the Orderville Canyon hiking trek is a 12 mile route through 3 foot wide slot canyon. Start upstream off North Fork Road and head downstream to the Virgin Narrows River Trail. This is a very difficult route requiring climbing equipment to descend numerous high drops. At the Virgin River, the trail follows the river bed downstream. You will be wet the entire time, and for most of the year, gators and water shoes are required. Watch out for flash floods which can raise the water to 30+ feet deep in minutes.
The trailhead is off North Fork Road north of the East Entrance.
Overall, Orderville Canyon is the 22nd most popular hiking trail of all 38 hikes in Utah.