Only 4 miles from the crowds at Trillium Lake, the Upper Salmon River Trail offers solitude and the feeling of immersion into the depths of the Salmon Huckleberry Wilderness. Though lacking in great views, the hike offers an enjoyable ramble through a variety of terrain ranging from the dry ridge above the Salmon River drainage to the dense, damp rainforest terrain of the Salmon River Canyon. Although the overall distance and elevation change hints at a moderate level of difficulty, the reality of the trail conditions and exposure makes this a challenging hike.
Two trails begin from the parking pullout, and signage indicates the Salmon River Trail to the right. Start here, with a steep descent to a crossing of Mud Creek. You may want to keep this spot in mind for a quick dip on the way back up. After crossing a log bridge, the trail ascends steeply over a ridge to a trail junction at Fir Creek. A short walk to the left, at the top of the ridge, leads to a rocky outcropping with views of the surrounding wooded peaks (but no Cascade Peaks). At the junction, head right and uphill to follow the Fir Creek Trail, forming the outer reaches of the loop. This trail follows just below a ridge through a relatively open fir forest filled with huckleberry and rhododendron for about a mile. After another mile, the trail descends into the canyon. A word of caution here: from this point to the river, the trail is not well-maintained. The trail is faint in places, and frequently you have to push through dense rhododendron stands. It is slow going, but fortunately it is downhill all the way to the river.
After about a 1.5 miles, the trail meets the Salmon River Trail at an unmarked but obvious junction. Heading left will continue the loop, but it is worth a short detour to the right for a quarter of a mile. You will pass a mossy, flat area with towering cedars, which is a good lunch spot that offers access to the Salmon River (and a possible swim). Continue a little further on the detour to reach Pretty Creek, which can also be followed a short way to the river. From here, turn around and continue east, upriver, along the Salmon River Trail, which follows along a bench just above the river for about a 1.5 miles before climbing gently to back to the trailhead.
The trip could be also be done as a there-and-back by heading left at the first junction and staying on the Salmon River Trail, avoiding the more challenging section of Fir Creek Trail. Also, the entire Salmon River Trail would be a great trip with a shuttle, allowing hikers to start at this trailhead and finish at the lower Salmon River Trailhead.