Ranked among the lowlier 13ers, Sheep Mountain D is a Class 2 hike with a broad and flat summit finish. In our proposed route, Sheep Mtn. is part of a 4-day backpacking-climbing trip. Vehicle access to the Endlich Mesa trailhead requires better than average clearance, 4WD useful, but aggressive 4WD not required.
From the trailhead parking area, the trail (#534) heads NE on a switchback path of an old, highly rutted roadbed toward Endlich Mesa. We found a trail that ran somewhat parallel but which avoided the half dozen switchbacks by taking a more direct route upward. A steady but fairly gentle climb for a mile brings you to treeline. When we hiked this, the trail was covered with sheep prints and numerous smelly deposits. Once on the open ridge, there will be several miles (about 5) of open, tundra hiking with distant, spectacular vistas in most every direction except east. Take the opportunity at times to walk off the trail to the east and gaze down into the basins where we spotted elk on more than one occasion. The trail remains easy to walk and just as easy to follow, cresting out at about 12,200 ft.
After about 5 miles the trail crossed a small ridge and there was a fork to the left. Take this fork that heads down to City Reservoir #1 in the City of Durango watershed. Unlike the City of Boulder watershed in the Indian Peaks, you can legally enter here and even camp without threat of prosecution. The trail drops steeply down initially for a knee-bashing descent of 1,400 vertical feet to the reservoir. Remember that when you leave this area, you may have to pack back up this section of trail. You may observe some nice wildflowers along the way. The Trails Illustrated map shows the trail branching down near the reservoir. Either fork will get you there, but the right fork, may be a little shorter if the trail is still visible. Cross the dam at the south end and walk along the west shore toward the NE and the upper end of the reservoir. There is a nice campsite at that NE end on the edge of the trees with easy access to the lake. Streams are nearby for fresh water. The largest campsite can accommodate several tents easily, while nearby are several other smaller campsites. It took us about 4.5 hours to make this backpack in.
From the proposed base camp at the NE end of City Reservoir #1, head north on the trail up to Lake Marie hiking steeply up the forested drainage. In the vicinity of where the USGS map indicates to site of "Logtown," cross the creek to the NE. In 2006, we found a rock cairn marking a place to cross the stream where it passes over some rocks. After crossing, we bushwhacked up steeply through some willows on a fairly well-defined trail that showed passage of horses recently. The trail eventually took us on the east side of the creek that drains Castilleja Lake (Durango Reservoir #4). We passed a nice campsite on the way up along this stream in the open area that the map shows NE of Logtown. In the upper reaches of the valley, the trail fades away, but hiking is easy and quick across tundra and grass. Walk on past the three small tarns south of the two larger, unnamed lakes. Just before where this valley drops off steeply to the north, contour east and work your way over into another large valley/basin that heads eastward to Amherst. This basin will also be filled with tundra and grass until you come below the SW face of Amherst. The upper end of the basin becomes mostly broken rock.
At the time we made this climb, the only beta we had was the 'Guide To the Colorado Mountains" which said to "hike" up the SW face of Amherst, then to continue over to Organ. That was certainly an understatement. The word "Hike" is not an adequate description for the rocky and steep SW face. From here, note that there are two basic ways to the summit that we will mention. Looking over to the south ridge of Amherst, you'll notice a significant notch with a reddish gully that runs up to the notch. "Furthermore" on LoJ went up that gully to the notch, rating it a 3rd class scramble, but did not proceed up the south ridge, Instead, he angled over to the Amherst/Organ saddle and climbed Organ first, then went back to the saddle and ascended Amherst by its east ridge. His account is not very clear as to how he descended Amherst, but it sounds as though he descended the south ridge back to the notch. He does not mention anything harder than 3rd class. We did not choose to go that way, but our notes observe that the notch and the south ridge would have been easier than how we went.
The route we took went directly up the SW face. We walked up a moderately steep runout slope until it steepened and we began to scramble up the main face. We headed in the general direction of a dark, almost black crack, staying to the left generally. At one point we found ourselves navigating a steep, sloping shelf covered with loose gravel. We actually used a short piece of rope here to belay each other up this shelf with one of us taking the lead ascending a short, but near vertical step to another shelf from which a belay could be offered. This was only for a few feet, but this was the crux, 4th class section. The rope was mainly used because of the loose gravel. The upper shelf really offered nothing to belay from. Once above this crux, things eased up a bit. A little further up, we found a steep ramp leading right that brought us out on the south ridge, and east flank of the peak, just below the summit for a more pleasant finish. Looking back down the south ridge to the notch mentioned earlier confirmed to us that the notch and south ridge/east flank combo would have been simpler. This is one of those cases where we do not recommend our own route.
From the summit, you'll enjoy a good view over to Organ Mountain which pairs very nicely with Amherst if time and weather allows. There's also a great view looking across Johnson Creek to McCauley and Grizzly.
Organ Mountain is sequenced with Amherst Mountain before and UN13,105 following. Mileage and elevation gain estimates are measured from Amherst. From the summit of Amherst, head back SE along the summit ridge, then descend the east side/ridge of the mountain toward the Amherst/Organ saddle. This east flank is steep but easy to navigate, being comprised higher up of small, granite gravel, interspersed with clumps of tundra and flowers and some boulders. More tundra becomes dominant lower down. It only takes about 15 minutes to make this descent.
Begin ascending Organ along the SW face and ridge on similar terrain, encountering more granite gravel higher up. The first 200 feet are easy with spectacular views looking down into Johnson Creek and across to Echo Mountain, if you're close enough to the ridge. The upper/final portion of Organ is fractured into great blocks of granite, much like Sunlight Peak, but far less of it. To gain the summit, we circled to the right some and hiked steeply up into these blocks to find a path to the summit. Depending on your choice of path, you may have a little 3rd class scrambling. Have some fun wit it. At the base of the summit block, you'll find it to be one of those one-person-at-a-time type summits. Take turns to make the 3rd class scramble to the top. If you want to stop for lunch, you'll have to find a place nestled in between the boulders.
Sheep Mtn. D is sequenced with Amherst Mtn., Organ and UN13,105 with Sheep being the last leg of the day, though this route could be easily reversed. Mileage and elevation gain are measured from the summit of UN13,105. From that summit, unless you want some rock scrambling opportunity by descending directly down the south ridge of UN13,105, retreat back along the NW ridge until you can drop west and down to more even terrain. A bench formation leads over to the UN13,105-Sheep saddle. Hike south across tundra toward Sheep Mtn. Avoid a couple of rock towers by staying well below the ridge line on the west and delaying the beginning of your ascent of Sheep until past the towers. As you begin to ascend Sheep, continue to stay on the west side of the ridge to avoid problems as the slope steepens. Ledges will enable you to gain elevation and avoid minor cliffs, and a gully will help you attain the large, flat summit area. "Furthermore" on LoJ reports a couloir on the east side of the ridge that has some 3rd class spots in it.
From this final summit (unless you want to bag a few 12ers), looking south you see a huge tundra plateau that stretches all the way to Sheridan Mtn. to the south. That tundra plateau is also covered with flat, granite outcrops and slabs with numerous small streams and beautiful flowering spots interspersed among the slabs. The summit of Sheep Mtn. offers an impressive and expansive view in all directions as well as a great place to linger and soak in some sun. From here, it will be an additional two miles to return to the base camp at Durango Reservoir #1. Drop west from the summit on a mostly tundra-covered slope and begin a descent into the myriad of low rock outcrops, ledges and slabs as you weave your way down to the unnamed drainage that drops directly west to the reservoir and the suggested base camp. You'll find yourself in another prime elk habitat area. We saw a large herd of more than 70 here. A small pond that shows on the USGS map at 11,860 ft. was also surrounded by a large, flat, lush grassy area that elk would love. There are also some nice photo opportunities with wildflowers and small waterfalls as a backdrop.
As the basin begins to lose elevation more steeply, the elk trails will dwindle, so just stay on the north side of the creek and work your way down through the forest back to the base camp area by the reservoir. The entire loop of Amherst, Organ, UN13,105 and Sheep took us about 9 hours. We lost more than a half hour waiting out a couple of rain showers.