Upper Zion Canyon is probably the most famous backcountry area in the park, yet it’s also one of the most strenuous. There’s no trail and you’ll be wading much of the time in the river, which is usually knee- to chest-deep. In places, the high, fluted walls of the upper North Fork of the Virgin River are only 20 feet apart, and very little sunlight penetrates the depths. Mysterious side canyons beckon.

Hikers should be well prepared and in good condition—river hiking is more tiring than that over dry land. The major hazards are flash floods and hypothermia. Finding the right time to go through can be tricky: spring runoff is too high, summer thunderstorms bring hazardous flash floods, and winter is too cold. That leaves just part of early summer (mid-June–mid-July) and early autumn (mid-Sept.–mid-Oct.) as the best bets. You can get through the entire 16-mile (one-way) Narrows in about 12 hours, although two days is best to enjoy the beauty of the place. Children under 12 shouldn’t attempt hiking the entire canyon.

Don’t be tempted to wear river sandals or sneakers up the Narrows; it’s easy to twist an ankle on the slippery rocks. If you have a pair of hiking boots that you don’t mind drenching, they’ll work, but an even better solution is available from the Zion Adventure Company (36 Lion Blvd., Springdale, 435/772-0990, www.zionadventures.com) and other Springdale outfitters. They rent specially designed river-hiking boots, along with neoprene socks, walking sticks, and, in cool weather, dry suits. They also provide a valuable orientation to hiking The Narrows. Boots, socks, and sticks rent for $17 per day, $26 for two days; with a dry suit the package costs $39 per day, $59 for two days.

Talk with rangers at the Zion Canyon Visitors Center before starting a trip; they also have a handout with useful information on planning a Narrows hike. You’ll need a permit for hikes all the way through The Narrows—even on a day-trip. No permit is needed if you’re just going partway in and back in one day, although you must first check conditions and the weather forecast with rangers.

Permits are required for overnight hikes; get them from the backcountry desk at the visitors center the day before you plan to hike or the morning of your hike (8 a.m.–noon). You will also be issued a plastic bag that’s been specially designed to collect human waste. Only one-night stays are allowed. No camping is permitted below Big Springs. Group size for hiking and camping is limited to 12 along the entire route.

A downstream hike saves not only climbing but also the work of fighting the river currents. In fact, the length of The Narrows should only be hiked downstream. The upper trailhead is near Chamberlain’s Ranch, reached by an 18-mile dirt road that turns north from Hwy. 9 east of the park. The lower trailhead is at the end of the Zion Canyon Scenic Drive. The elevation change is 1,280 feet.

A good half-day trip begins at the end of the Riverside Walk and follows The Narrows 1.5 miles (about two hours) upstream to Orderville Canyon, then back the same way. Orderville Canyon makes a good destination in itself; you can hike quite a ways up from Zion Canyon.

During the summer, Zion Rock and Mountain Guides (1458 Zion Park Blvd, 435/772-3303) offers a daily shuttle to Chamberlain’s Ranch, leaving at 6 a.m. Make shuttle reservations between 9 a.m.–6 p.m. on the day before you want to ride. The fee is $28 per person, with a small discount if you rent gear from them. Zion Adventure Company (435/772-0990) has a similar service.