Length: 4.1-miles (one-way to Flattop Mountain)
Trailhead Facilities: None
Short Trail Summary: This trail is not a point-to-point hike. The middle section of the trail is unmarked on forest service maps as disputed public land or private land. Only the western segment of Fish Creek Trail is described.
Hiking to Flattop Mountain has an elevation gain of 3,000-feet, is secluded, occasionally steep and remarkable at the top.
To reach Fish Creek Trail begin your hike at the Opal Lake Trailhead and follow that description for the first .9-miles. Veer to the east at the marked junction on a faint trail that soon enters an aspen stand. After 1.7-miles the trail begins a more assertive climb via switchbacks to an unmarked saddle. Pick a northerly direction on an unmaintained, but sometimes easy to find, trail to the top of the ridge and the true summit of Flattop Mountain at 11,463-feet. There is a summit register.
Directions: From US 160/US 84 junction, turn south onto US 84. Travel 8-miles and turn northeast onto Blanco Basin Road (CR 326), a gravel road. After 9.5-miles turn south onto FS 600 (Castle Creek Road). Continue for 3.3-miles to FR 023 (Opal Lake Road). Turn south and continue an additional .7-mile to the trailhead.