The Virgin River is a shallow river that starts north of and runs through Zion National Park. Hiking the 16 miles of the Virgin River Narrows through the park is a spectacular experience with sheer rock walls rising hundreds of feet straight up. You are in water most of the time, and it can be dangerous during times of heavy rain and flash floods. Park Service permits are required. Tubes can be rented in the town of Springdale south of Zion for more low-key river play.