Thunder Pass Trail

This is a full-day out-and-back from Colorado River Trailhead to Thunder Pass, about 14 miles round trip. Follow Colorado River Trail past Lulu City, continue by connector to the Grand Ditch corridor, then climb to the pass. The mapped corridor is about 7 miles one way and is stored once; the hiking distance includes the return on the same route. Budget roughly 8–10 hours. Shorter walks that end at Lulu City or begin farther along Grand Ditch cover different itineraries.

The first stretch is broad and mostly level beside the Colorado River, with trees along the way to the old Lulu City site. The silver-mining settlement briefly grew during the boom around 1879; scattered structural fragments remain. After Lulu City, a steeper connector rises toward Little Yellowstone Canyon and the higher Grand Ditch corridor.

The Grand Ditch is a high, historic waterway with a relatively level track and open views toward the Never Summer Range and Continental Divide. Beyond it, Thunder Pass Trail climbs steadily to a grassy saddle between Lulu Mountain and Static Peak, around 11,300 feet. The view opens over the forested valley and surrounding ridges. For a photo, frame the grassy saddle in the foreground with the valley beyond; return the same way.

The long approach and final high-altitude climb make this a strenuous outing. Colorado River Trailhead is on Trail Ridge Road, about 10.2 road miles north of Kawuneeche Visitor Center. Weather changes quickly at elevation, and snow or ice can linger on high trails into summer. Pets are prohibited on park trails.