The flow never stops on this trail. As the name implies, it stays on the rim of a canyon, which is also the wilderness boundary (but not in the wilderness!). The trail actually goes on farther, but as it is shown here it turns around at the wilderness sign at Buck Mountain, but it will be a long ride if you do it here and back.
There are hundreds of miles of singletrack in the La Grande area, and this is just one of the the many good ones.
Need To Know
This trail has grown in popularity recently, especially for horseback riders. On Saturdays you might run into some but overall trail use is very low because of the low population density. Motorbikes also use it, but not that often and they've improved the flow and they cut out trees for us. If you go on a weekday you probably won't see anyone.
The ride basically goes like this: old growth forest flow, pop out on a ridge with a sweet view, wrap around to the treeless side of the ridge for a better view, repeat. Usually people start at Horseshoe Prairie trailhead or Andies Prairie SnoPark (same entrance for both), and then they ride it to Ninemile Ridge. From there, they come back on the trail or take the paved Summit Road back. Ninemile ridge is only about half of the fun though, as the route here shows you how to take the trail all the way to the legal end for mountain biking.
Other points of interest include a crashed WWII plane, and plenty of bear, cougar, and elk.
There are many other trails in this area, so check out other rides around La Grande.