The San Rafael Desert (also called San Rafael Reef or San Rafael Swell) is located 20 miles west of the town of Green River in Emery County in southeastern Utah. San Rafael Reef is a gigantic uplift anticline about 50 miles long crossed by Interstate 70 (entering the reef into Spotted Wolf Canyon) and by the San Rafael River cutting the reef into the deep narrow canyon called "Black Box". There are no service in the whole area and most of the unpaved backcountry roads are rough and lead visitors to very remote areas. The natural arches there are difficult to visit. Sometimes they are perched on the top of the reef, accessible after a very long day of hiking or canyoneering. A topographic map and sometimes a guide is needed for most people to explore this incredible secretive landscape. Mystery Arch is one of the most beautiful arches of the area. This double arch sits well hidden near the top of the reef. Many of the significant arches reported in this area were found recently in the nineties.