There’s a network of multi-use trails here in the Stack Rock Reserve, so the out and back to the rock is only one possibility for a hike, run, or bike ride in Boise’s local mountains. As mapped here, the hike begins from an unmarked pullout along the road. Parking there is limited, so if it’s full you might have to drive farther up and park at the officially signed Stack Rock Trailhead, which adds some distance to the hike.

Stack Rock is popular at all times of year, especially in the summer when the valley is hot. At this elevation, temperatures drop quickly in the fall, and you’ll catch color in the deciduous trees by late September. Conifers are prevalent along the trail, however, remaining lush when the mountains turn white in winter. Snowshoes or spikes might be necessary then, depending on firmness of the snow. In spring the trail gets muddy as the snow melts, and although people still go, it’s best avoided until late spring when the tread has had a chance to dry out, and when wildflowers begin coloring the slopes.

Source: https://www.cityofboise.org/departments/parks-and-recreation/parks/stack-rock-reserve/