Park at the Painted Desert Inn National Historic Landmark (2 miles from the north entrance of the park). If you know where to look, you can actually see Onyx Bridge from the overlook. Looking at the inn from the parking lot, the trail begins with steps to the left just behind the upright display signs. Take the steps down to the switchback trail that descends 300 feet down to the valley floor. Please be careful of the loose pebbles.