This is a great bang-for-your-buck hike in terms of proximity to town, great views, and aerobic exercise in a relatively short trail. The only disappointment is that it ends at the drive-up overlook at Dobbin's Lookout. There is no need to linger among the crowds, because the view is equally impressive while returning down the trail.
Holbert Trail begins from the Activity Complex outside the main park entrance station. It climbs the north slope of South Mountain through a wide canyon and continues to eventually connect with National Trail. An obvious spur trail leads to Dobbin's Lookout at the top of the canyon.
The trail begins rather blandly in a series of sandy washes and along a paved service road, but this section is short. Then the climb begins, immediately rewarding with views over Phoenix and the surrounding mountains. The scenery only gets better the higher you go, with craggy rock formations and an abundance of saguaros all around. The trail maintains a steady gradient and is rocky in places but is never overly steep.
The terrain offers little shade, so it is not recommended for midday or in especially hot weather. Water is available at the trailhead only. Dobbin's Lookout has toilets, benches, and shade structures, but no water, so bring plenty for both directions of the hike.