A Rainbow Turned to Stone Rainbow Bridge is one of the world's largest known natural bridges. The span has undoubtedly inspired people throughout time--from the neighboring American Indian tribes who consider Rainbow Bridge sacred, to the 85,000 people from around the world who visit it each year. Please visit Rainbow Bridge in a spirit that honors and respects the cultures to whom it is sacred.
The 23 mile trail is from the Navajo Mt. Side. There's a trail on the Lake side that is accessible by boat only. There is tour boats that go there. The trail is around 1/2 - 1 mile depending on lake level. Best to get there early because most of the trail is in the shade. Always remember any trail in the Lake Powell area. You need to carry water. It is a desert.
My then-girlfriend (now wife) and I hiked the South Trail into Rainbow Bridge. (The map on this site shows the North Trail.) It was a truly life-changing experience. We didn't see another soul over our 3 days on the trail. Be careful: the first water is at the 9-mile mark. Also, there's a lot of elevation change. You work your way in and out of steep canyons for the first 6 miles. The NPS link I pasted below has a pretty good description of the trail. I'd recommend that you ask one of the local Navajo if you can park on their property. They'll keep your vehicle safe. We parked at Marlo's house and paid $20 as a courtesy. He and his wife were very friendly.