There are two ways to access the upper West Fork of the Cimarron River. One comes in off US 550 from a little north of Ridgway and the other comes in from US 50 and goes by Silver Jack Reservoir.
From US 550 turn east onto County Road 10 which is marked for Owl Creek Pass. This turnoff is 1.8 miles north of the single light on US 550 at the intersection for Ridgway. From here, just stay on CR10, avoiding any other options. The road goes mainly through open meadows or alongside pinyon/juniper forests. Watch for it making a right turn where County Road 8 comes in from US 550. (If coming from Montrose, CR8 can be used as a shortcut.) At the turn, you will now be on CR8. Follow it past the Sleeping Indian Ranch and across Cow Creek. A little further up valley, the road makes a sharp switchback and begins gaining elevation more seriously through open scrub oak terrain. Soon, you'll pass the Forest Service sign and enter FS land. The road tends to degrade some here but passenger cars driven carefully can continue. The Forest Service designation for the road is 858. It's a long slog to the top of Owl Creek Pass - usually requiring around 45 minutes of drive time. When you get to "True Grit" meadow that offers the nice view of Courthouse & Chimney Rock, and is usually filled with corn lilies, you're almost there.
At the top of Owl Creek Pass, there's a small, unofficial camp area on the north side of the road. Continue down east to the first turnoff you see, less than a half mile from the pass. This road to the south is FR860. Drive up this usually good road that offers several possible campsites all the way to the Courthouse trailhead (about 1.7 miles from CR8). A short distance past the trailhead, passenger cars will need to stop. There's some limited parking there. It will be obvious where you need to stop. The main road veers to the right and becomes much worse.
If you have 4WD with good clearance, continue south up the road as it goes up a steep, rocky section, then levels some as it passes through a section with large potholes. In .75 mile, it drops down a little and makes a sharp left to a ford of the West Fork. There are some good campsites here. The ford is a low water crossing and can be difficult in earlier season. Use good judgment. If you can't drive across, walk upstream a good distance to find perhaps a fallen tree across the stream. From the stream crossing, it's another.7 mile to the trailhead. This is not a graded lot. It's basically just the end of the road. Park where you can find room & it's not too rocky.
If coming from Montrose, by way of US50, drive past Cimarron about 2.7 miles and turn south on County Road/Forest Road 858 that goes to the Silverjack Reservoir. From Gunnison, drive west on US50 past the Blue Mesa Reservoir, down through a narrow canyon section, up over a pass at 8,700 ft., then down a long and winding descent toward Cimarron. The turnoff is one mile past the turnoff for CR864 and just past a small resort on the south side of the highway. It's a long, 22 miles drive back on a graded, dirt road, suitable for passenger cars, but can be dusty and/or washboarded. Continue past the Silverjack Reservoir about a mile and then make a right turn to cross the creek and then continue driving on FR858 to Owl Creek Pass. The turnoff for FR860 will be just after a major switchback and about 6.5 miles from the right turn that takes you across the creek after driving past the Silver Jack reservoir. See information above for the drive up FR860.
If coming from US550 on CR10 & CR8, the best camping will be at "True Grit" meadow on the west side of Owl Creek Pass; at the top of the pass; or along FR860 as it goes south up along the West Fork. There are numerous spots along 860, many of which will be occupied on a weekend. See also our CalTopo map for some of the closest spots to the trailhead.
If coming from US50 & the Silver Jack reservoir, there are three Forest Service campgrounds just north of the reservoir and then after making the right turn beyond the reservoir, there's an area with numerous campsites along FR861.A1 Otherwise, if you want to camp more closely, continue to FR860 and find a spot along there as described above.
Note: This route description assumes the use of a 4WD with good clearance to reach the trailhead. If you only have use of a standard passenger vehicle, add 1.4 miles one way to the distance and another 350 feet of elevation gain.
From the trailhead parking, head south of Forest trail #226, which eventually goes over a pass into Wetterhorn Basin, but you will not be going that far. There is a trail register at the start. The trail leads through mostly open meadows the first half mile rife with wildflowers at the right time of the summer. As you're walking along, be sure and identify which peak is Fortress and note its west ridge that drops down to the valley floor. You want to make sure you walk south up the trail far enough to be past that west ridge. That will mean a distance of about 1.2 miles. As the trail begins to enter and stay in some trees, you'll cross one drainage which may or may not be running and then another. Cross both, but a little past the second is where you'll need to leave the trail and head generally east on the south side of that drainage. This is the first drainage south of the west ridge of Fortress. If you have GPS, these coordinates should help identify the approximate spot: N 38° 05' 52.72" W 107° 32' 55.48". You don't have to be in the exact spot.
Bushwhack east along the side of the drainage/creek for a while. You may find a cairn or two and faint trail. After a few hundred yards, it may become easiest to enter the drainage and walk in it if dry or running low. Continue up the drainage until you see a dry fork coming in from the left with rocks, tundra and grass. Head up that way. If you're in the right place, above the head of this dry fork, you'll be looking directly at the large, cliff/buttress on the west ridge of Fortress. Do not try to continue in the main drainage. In this left fork, there will be some rocks & boulders to get around and it is fairly steep. As you hike upward, you'll notice a ridge on the right side with some trees. Exit this drainage just above where the trees end to gain the ridge. Walk steeply uphill now on grassy tundra toward the lower cliff band. There will be two possible breaks in the cliff from which you can choose. One almost directly above and the other a little further to the right. Either one will get you through to a sloping bench area below the second cliff band with no more that a brief 3rd class scrambling move.
Once below the second cliff band, in the immediate area, look for another break close by that allows a brief 3rd class scramble again for about 30 feet and takes you through the cliff. There are several places in the cliff that will seem to offer a possibility, but this spot will appear as the easiest. It is fairly narrow. Exposure is minimal. You may want to send people through one at a time. Once above, the terrain changes to more sparse vegetation and small scree & talus. Note that it is also possible to walk along the sloping bench below the second cliff band eastward until the cliff plays out. You can then just walk on up and head back over to the west ridge.
Once through the two cliffs, it's steep but easy walking to the summit on mostly small scree. Some of the drops to the north off the ridge offer nice views. We've observed a pair of golden eagles flying here. Ahead, looking up the ridge, you'll see the summit block guarded with a sheer cliff. Don't worry - it's easily circumvented. As you approach the summit, one brief section of the ridge will narrow and drop off on either side. Beyond that, it's a stroll to the summit.
On the summit, with a well-built summit cairn, if you look north, there's another summit just a short distance away that appears as high. No one to our knowledge is claiming that it is, which is probably good. To get to that point, you would have to come back down from the main summit a little, walk gingerly across and sharp, rotten ridge and then scramble up a very rotten looking conglomerate 15 foot wall. No thanks! If you're interested in either Precipice or Redcliff, you'll have good views either way and of the connecting, gnarly ridges. A report from someone who has done or attempted to do either of those connecting ridges would be interesting. We've heard rumors but nothing more.