The trailhead is located across from the turnout for Mammoth Crater, Mammoth Crater Trail
and Big Nasty Trail
. To find the trailhead, drive south for about 2.5 miles on a dirt road that begins immediately after the parking area for Bunchgrass Overlook. At the beginning of this road and to the west is an old cinder cone called Hippo Butte. After about 2.5 miles, there is a small turnout on the west side of the dirt road that is the parking area for the trail. The trailhead is located across the road from the turnout and is marked by a small sign. Follow the trail underneath Ponderosa pines as it meanders along the rim of Hidden Valley till it ends.
Hidden Valley is the result of a massive lava tube that collapsed.