Onyx Bridge Hike

Onyx Bridge Hike is an approximately four-mile out-and-back from Painted Desert Inn to an exposed petrified conifer in the Black Forest. The walk begins on a developed descent, then becomes a route-finding hike through sandy washes and small drainages. Choose it for a remote geology-focused outing; skip it if you need a continuous, signed trail. The namesake is a fossil log, not a footbridge to cross. The park's estimate is about two hours, but leave extra time for the unmarked terrain. This is separate from the seven-mile Wilderness Loop, though both enter the northern wilderness.

Park at Kachina Point beside the Inn, about two miles from the park's north entrance. The Wilderness Access Trail starts at steps on the building's left side, just behind the upright display signs. Those switchbacks drop roughly 300 feet to the valley floor. Loose pebbles make the descent awkward, and the climb back up is moderately difficult. The Inn stays visible from many points along the hike and can help you orient on the return.

The developed path ends at the bottom. The suggested route continues north toward Lithodendron Wash, following or crossing it to a bend, then turns west into a smaller drainage. At its splits, stay on the right side until a rockfall; climb its left side, where the log lies above and to the right. There is no continuous tread to follow through this section. Branching washes can look alike, so expect to stop and check your line rather than simply follow footprints. The route shown in the app is one mapped outbound corridor; the park's own directions describe it as a suggested line, and other walked tracks are longer.

The feature is an exposed Triassic conifer from the Black Forest Bed of the Chinle Formation, about 210 million years old. An older park handout describes roughly 30 feet of exposed fossil wood. Erosion continues to reveal and reshape the Black Forest's logs. A more recent field report says this log has broken into pieces and no longer spans the wash, so do not count on the intact bridge shape shown in older pictures; its present appearance has not been confirmed in a recent park account. Look for the petrified log and surrounding wash, and leave all fossil wood where it lies.

The hike reaches the Black Forest, where many petrified logs erode from the same geologic bed. The exposed conifer is the main reason to take this route, while the washes and colored badland slopes are part of the journey rather than a paved approach to a single viewpoint. From the Kachina Point overlook, the log can be seen if you know where to look; that view is useful for orienting yourself before descending, but it does not replace the route-finding hike.

The park warns that spring snowmelt and summer monsoon storms can bring high water, thick mud or quicksand to the washes, and says not to attempt the hike when lightning is nearby. Its route handout recommends at least a gallon of water per person per day. Restrooms and potable water are listed at the trailhead parking area, but no on-route water is documented. Pet guidance is unclear for the unmarked section: an older route handout permits leashed dogs, while current park guidance addresses developed trails. Check with the park before bringing a pet.