The area around Moab, Utah, is famous for its natural arches, and many are preserved in Arches National Park. Quite properly, of course, those arches are shielded from human activity, and some of them would certainly be at risk of damage if the crowds were allowed to swarm over them.
Still, it would be fun to actually walk across a natural stone arch, and Gemini Bridges let you do just that. This pair of robust arches are perfectly safe, and legal, to cross on foot. They stand on public land operated by the Bureau of Land Management outside of Moab. They’re also in the heart of the scenic red-rock country for which Moab is famous, so the area is worth a side trip for that alone.
One word of warning, though: the gap between the arches varies from around six to 10 feet, and there have been a number of fatalities from people attempting to jump between the arches. Don’t do this!
Know Before You Go
Gemini Bridges are off County Rd. 118, the Gemini Bridges Road, which runs between US-191 north of Moab and Utah SR-313, the Dead Horse Point road. The easier access is from the SR-313 side. Go 13.1 miles down SR-313 from its junction with US-191 to the Gemini Bridges Road junction, which should be marked. Turn left here and go about 5.5 miles to a turnoff to a well-marked trailhead, which will be on the south (right) side of the road. In dry conditions an ordinary passenger car should be OK, but high clearance is desirable particularly if there has been rain. The road from the US-191 side is both longer (about 8.8 miles) and rougher, and an exposed stretch near the beginning would be especially dicey in 2wd if it were at all wet. Its junction with US-191 is about 1.3 miles south of the junction with UT-313.
From the trailhead parking, which has room for multiple vehicles, the access trail heads generally diagonally to the left. Here and there splashes of paint on the bare sandstone act as trail markers. There are lots of use paths leading various ways, so they're a less sure guide.