The easiest and most popular route on a striking, dark-rock summit near Washington Pass, reached via the popular Maple Pass/Heather Pass trail network and a high camp at Wing Lake.
Drive to the Rainy Pass Trailhead (Heather-Maple Pass Picnic Site) on Highway 20. Follow the Lake Ann/Heather Pass trail about 1.5 miles to a junction, continue toward Heather Pass, and just below the pass take an unsigned right turn up into meadows, over the pass, and down the far side to a boulder field. Follow cairns toward Lewis Lake (a trail appears intermittently), pick up a clearer trail before the lake, and continue around it (either the longer trail on the north side or a rougher rock-hop along the south shore) to Wing Lake, a popular high-camp spot directly below Black Peak with views of the summit. From Wing Lake, head up the moraine and onto a permanent snowfield to an obvious col in the south ridge; when not snow-covered, the last 200 feet to the ridge is loose scree and dirt with poor footing. From the col, a climbers' trail leads up the south ridge; any of several Class 3 lines lead to the summit block, with easy Class 4 moves reported near the very top.
Descend the same south ridge and col back to Wing Lake; this is described as the most common and straightforward descent line on the mountain.