South of Sun Valley, the Greenhorn Gulch - Deer Creek Loop is a rolling 32 mile route with excellent views. The route runs through beautiful pine and aspen forest with some sections of past wildfire damage. The wildflowers are amazing during mid-June.
To reach the trailhead from Ketchum, head south on SR75 for 5.5 miles. Turn right heading west on Greenhorn Gulch Road for 3.5 miles to the trailhead parking area located at the end of the road.
Overall, Greenhorn Gulch - Deer Creek Loop is the 62nd most popular mountain bike trail of all 63 mountain biking rides in Idaho.