The best way to access this loop is to park a car at the Vallecito Campground and then either drive a second car or get a ride to start the run at the Pine River Campground.
The first 2.8 miles of the Pine River Trail #523
follows the Granite Peaks Ranch property line, so stay on trail. Soon reaching a meadow, the canyon walls begin to narrow, and the trail pulls higher above the creek. Gaining ground, the trail comes to a bridge crossing Lake Creek. 6.3 miles in, turn left onto the Emerald Lake Trail
The trail steepens beside Lake Creek, especially within the first 0.6 miles. But at 8700 feet, the walls retreat, allowing for a more gradual gain. Continuing 0.7 miles, the trail breaks out into a meadow before closing back in on the creek and easing through a stretch of heavy deadfall. After 1.2 miles, switchbacks clamber up an avalanche chute which provides access to Little Emerald Lake at 10,057 feet, then finally, Emerald Lake.
Deep in the canyon, formidable walls striped with steep drainages and avalanche chutes rise above both shores. The trail stays above the lake, not staying very close and barely offering a view. The thick canopy overhead offers protection from both the heat and the rain. Where Emerald Lake finally comes to a close, the views really expand. An easy stretch wraps slightly eastward. Vegetation thins, but campsites pepper the surrounding pockets from here until treeline.
About 2 miles north of the lake, switchbacks gain 1,200 feet beside the Lake Creek gorge. At treeline, the trail peters out at the shores of an unnamed lake. Turn right and follow the faint line through a wide band of willow thickets as the route wraps northeast into the heart of the basin.
The trail continues to a rocky spine beside the dry creek bed, where the tundra gives way to the scree. I lost the trail here, but trace the drainage and make a general line north to Half Moon Lake. The trail comes back full force and veers west towards a 12,500 foot pass between Half Moon Lake and Rock Lake. After gaining 275 feet, the trail levels on a false summit. Look right, and a large cairn denotes the true pass. From here, an easier descent loses 660 feet to Rock Lake. The Emerald Lake Trail
ends just above treeline, about 0.2 miles north of Rock Lake.
Turn left onto the Rock Creek Trail
. The split is unmarked and difficult to spot. The route first switchbacks down to treeline, then half a mile below the lake, drops out of the basin and into the Rock Creek drainage at the head of a meadow with far reaching views. The trail negotiates the exposed bedrock which might give the trail its name. Much of the route follows an easy grade down the narrow basin. As you drift in and out of meadows, the Guardian becomes more distinct and slowly overtakes the surrounding peaks. Within the final stretch, the canyon walls narrow into a second set of switchbacks that quickly looses 914 feet to meet with the Vallecito Trail #529
At an average 3% grade, the 14.6 miles of Vallecito Creek is the easiest leg of the loop. Turning left from Rock Creek, the trees open briefly before heavy timber and a thick undergrowth envelops the trail. Pulling west, the trail hugs Vallecito Creek at the foot of the steep hillsides. After 0.5 miles, as the shoreline grows too rugged, the trail climbs higher and the views slip away behind the basin walls. About 5.6 miles from Rock Creek, the trail comes up on the Needle/Johnson Creek Trail #504
. Continue on Vallecito Trail #808.
Swaying back and forth between both shores, gaining and losing ground, 7 miles of dense forest unfolds. The first bridge (of 3) is out, so you'll have to ford 40 feet to cross. The lower you run, the more the canyon narrows, and there aren't many good campsites to choose from anymore. At the last bridge, the forest transitions into the pondorosa, aspen and oak of the lower elevations. About 13 miles below the Rock Creek Trail
, and with only 1.6 miles to go, rocky outcrops give you a good look into the mouth of the canyon. Here, wooden homes dot the distant hills, your first sign of civilization. The trail really gets busy now. Steeper switchbacks loose 415 feet before finally feeding into the Vallecito Campground and your waiting car.
At a mile long, Emerald Lake is one of Colorado's largest natural lakes. It was formed by a massive landslide that gave way on the eastern wall of the basin, damming the south end of the lake. Like much of the San Juan Mountains, eons of glaciation lends its hand to the rugged beauty of the Needle Mountains, but the way it chiseled away at the mountain could have also played a part in bringing about this landslide.