The most popular trailhead for those climbing the peak is the one at Crystal Lake. Crystal Lake is reached from the Trial Lake spur road off Highway 150 25.7 miles east and north of Kamas. Follow the signs along the spur road to Crystal Lake. This gravel road is good for all vehicles. This is the trailhead for the north ridge; the most practical way to climb Haystack Mountain.
From the trailhead take the trail posted for Long and Island Lakes. The first part of the road is actually an old road that heads west and stays above Crystal Lake. There is a signed junction at the end of the old road. Follow the trail left for another mile while it switchbacks up to Watson Pass. To climb Haystack Mountain, simply get on the ridge to the south of the pass and follow it to the summit. There is no trail. At first, there are a few steep sections, and some boulder-hopping, but this is a fairly easy ascent. Once one the high ridge, just follow it south to the highest summit. The northern summit is slightly lower (by two feet) than the southern one. There are excellent views of the Wasatch Range, and much of the Uintas from the summit ridge. Dozens of lakes are visible from the summit as well. The hike is 2.75 miles one way to the summit.
A good pair of boots is needed.