At about 1135 Pacific time, a Cessna 180J nosed over during landing rollout at a backcountry airstrip in Death Valley National Park. Neither occupant was injured. The airstrips existence is not depicted on aeronautical charts and it is not maintained. The runway is only usable in a single direction. The airstrip is locally known as the Chicken Strip. The pilot said a wheel caught in a hole in the runways surface and the airplane departed the runway. The pilot said he had landed at the airstrip a half-dozen times in the previous 90 days.