Overview and Climbing Information
Brown Mountain is lower than its neighbor Mount Crosby, but the climb to it from Greybull Pass is more rugged and exciting. Like its neighbor, Brown Mountain looks over the type of pure mountain wilderness rarely found anymore in industrialized nations, a wilderness that in the Lower 48 exists principally, though not without exception, in Idaho, Montana, and Wyoming.
Climbing Brown Mountain is an undertaking requiring about 4 miles (one-way) and 3000’ of elevation gain. A Class 1 trail guides one for about 3 of those miles and 2300 of those feet, but it is in places so steep and in others so faint that it often feels more like Class 2. The rest of the way is as easy as Class 2, much of it on talus, but those wanting a little more excitement can find and enjoy a Class 3 section shortly before the false summit. The short of it is that you hike to 11,480’ Greybull Pass and then head northeast along the ridgelines to reach Brown Mountain.
If you want to make a longer day of it, pair Brown Mountain with Mount Crosby, which is on the other side of Greybull Pass, or make it part of a traverse that includes Galena Ridge, Chief Mountain, and a finish at Meadow Creek Trailhead (or back at Kirwin via a loop; please see the attached route page for details about this outing).
From the east end of the Kirwin parking area at 9200’, a trail starts heading north and uphill. This is the Brown Basin Trail. There was a sign indicating it as recently as July 2007, but if there is no sign, look around for the trail. There is only one leaving the parking area.
For about a mile, the trail climbs switchbacks through sagebrush and trees, and good views are almost always present. When the switchbacks end and the trail starts heading straight up to timberline, the trail becomes faint in places and sometimes disappears entirely. Look for cairns, some of which may have wooden posts jutting from them.
As you enter Brown Basin, take care to stick to the trail, as you are walking amidst delicate tundra. Even though the basin has steep mountain walls flanking it on all sides but the one you have hiked up, it feels vast and very open. At about 11,000’, the trail crosses to the right of what is left of the stream draining the area. Just past here, you may see a faint trail going straight while the main trail bends right. Do not take this faint trail. First, a small rock pile blocks it, indicating it is closed off (an attempt to heal a scar on the landscape). Second, it peters out very quickly, which is obvious from above.
The main trail follows long switchbacks that almost feel easy because of their length and gentle grade, but make no mistake—they get you up. Close to the pass, you will reach a trail junction. The left fork seems to head toward Crosby’s ridges and cut off some distance, but it does not. In fact, it actually follows a pair of long switchbacks to reach the right fork just a few feet below the pass. The right fork climbs steeply on loose dirt to the pass. So take your pick.
Greybull Pass is a spectacular destination all on its own, with views deep into the wildest parts of the Washakie Wilderness. There are also several pinnacles and gendarmes flanking the north side of the pass; what looked so gentle from Brown Basin has an entirely different character on its other side.
Start climbing northwest. From below, the cliff bands between the pass and the summit may look troublesome, but they can be bypassed on either side. These, though, are the cliff bands that offer some Class 3 fun, and they are worth doing. Besides, it is easier, I think, to climb what here is pretty good rock than to slog along more talus. Again, take your pick.
Above the short scrambling section, what looks like the true summit appears as a bump on the ridge straight ahead. It is Class 2 all the way and takes 5-10 minutes to reach. The true summit, though, is a flat, slightly higher spot about a minute's walk from the bump. It was covered in snow when I was there, and I do not know if there is a cairn or register there.
You will have to drive to the Kirwin trailhead. 4WD is recommended, but high clearance and AWD will suffice under most warm-weather conditions. Kirwin was a mining boomtown many years ago, and several structures still remain in the area. The ruined townsite is a popular destination for locals who like to drive up for lunch and a tour, but few people outside the area know anything about Kirwin and the awesome trail system it accesses. Kirwin is also one of the most beautiful trailheads in the Rockies, with towering, brooding mountains all around it.
From Meeteetse, 32 miles south of Cody, turn west onto the signed road for Wyoming 290. In 6.4 miles, turn left onto Wood River Road. At 11.6 miles, the pavement ends. The national forest boundary is at 21.7 miles. Pass Wood River Campground at 22.4 miles and Brown Mountain Campground at 24.8 miles. The road now gets a little rougher, but it is not real 4WD stuff. At 26.8 miles is the first of four stream crossings. This one is short and usually shallow. The second river crossing is at 27 miles. This one is wider and deeper. The third crossing, which is actually two crossings in quick succession, is at 29.3 miles. These are broad but shallow. The last two miles to the trailhead are rocky but not anything to get nervous about. There is one more stream crossing just before the trailhead, but it is a tributary stream and may even be dry. The trailhead is at 33.1 miles. It took me 75 minutes to make the drive.
NOTE: In late spring, early summer, and after storms, the stream crossings could be difficult or dangerous, so get out and test them before you plow through. I have made it through in a Subaru Outback, but the crossings on the way out were a little sketchy for that car, as the stream was swollen with the previous night’s rain.
Red TapeThis is prime grizzly country, which means special rules about food storage and personal behavior are in order. I will not list them all here. Bottom line: If you don’t know, don’t go.
Road construction may affect access. It would be wise to check with the local ranger district about any access restrictions before heading in. Call 307-868-2379 (Meeteetse Ranger District).
CampingCamping is available at the Wood River and Brown Mountain Campgrounds (see Getting There about directions). The sites go on a first-come, first-served basis, and there is a $10 camping fee. Water and pit toilets are available at both.
You could also sleep in your car at or near the trailhead.