Sacagawea Peak is fairly accessible from Bozeman and—because the trailhead is already at 7,788 feet—it makes for a great, easier, summit-bagging experience. The popular trailhead is also the access point for the beautiful Fairy Lake, which makes for a perfect warm-up or cool-down add-on to this hike.
From Bozeman, follow Bridger Canyon Drive (Highway 86) north. Turn left of Fairy Lake Road (Forest Road #74), and drive 6.2 miles to the road's end at the Fairy Lake Campground and Trailhead. Parking shouldn't be an issue, but both Fairy Lake and Sacagawea Peak are popular routes, so it may be busy.
From the trailhead, the Sacagawea Pass Trail #518
trail begins in a forested area, but very quickly transitions to open meadows and rocky slopes. Because the route gains 1,800 feet in just over two miles, most of the trail is consistently steep as it switchbacks up the mountainside. The final switchbacks are tight and there are numerous social trails cutting the corners—please respect the area and stay on the main trail!
At 1.4 miles, the Sacagawea Pass Trail #518
ends at the Bridger Divide, the pass between Sacagawea Pass to the south and Hardscrabble Peak to the north. From the pass, the Corbly Gulch Trail #544
drops off the other side to the west (this trail is an alternative route to the summit of Sacagawea Peak, but it's a far longer trail with even more climbing). The Bridger Foothills Trail #534
heads south, but contours or descends as it passes below Sacagawea Peak and Naya Nuki Peak). And the Bridger Ridge Trail #513
goes south as well, but a bit to the left and begins climbing immediately.
For the final 0.6 miles, the trail winds its way south before turning east for a final push up a series of switchbacks to the summit. The views from Sacagawea Peak, are spectacular, and consist of the Crazy Mountains to the east, the Tobacco Root Mountains and the Spanish Peaks to the west, and the rest of the Bridger Mountains to the south. If one summit isn't enough, follow the ridgeline for another 0.5 miles to Naya Nuki Peak.
After a summit snack, head down to the pass, and then descend back to Fairy Lake—the Fairy Lake Trail
makes for a lovely, little, 1.0 mile loop as well, or just follow the 0.2 mile spur to the lake for a quick view of the lake's blue waters.
The Bridger Mountains are known for mountain goat sightings, so keep an eye out while up high!