Stacy Ann Arras was 14 years old when she disappeared during a horseback trip in Yosemite National Park, California. On July 17, 1981, she was riding the High Sierra Loop with her father, George Arras, two guides, and several other members of their group. That afternoon, the group arrived at Sunrise High Sierra Camp, where they planned to spend the night.

After changing clothes, Stacy picked up her camera and said she wanted to walk to a nearby lake to take photographs. She first asked her father to go with her, but he declined. A 77-year-old member of the group, Gerald Stuard, offered to accompany her instead. The two walked down the trail together toward the lake. After a short distance, Stuard became tired and sat down to rest while Stacy continued walking alone toward the lake. He watched her disappear behind a stand of trees, and that was the last confirmed sighting of her.

When Stacy did not return after about 20 to 30 minutes, Stuard went back to the camp and alerted the others. Members of the group immediately began searching the area before notifying park authorities. The National Park Service organized an extensive search that included helicopters, search-and-rescue teams, tracking dogs, mounted personnel, and dozens of volunteers. Searchers covered the area around Sunrise High Sierra Camp, nearby lakes, forests, meadows, and steep terrain, but no confirmed trace of Stacy was found.

Investigators considered several possibilities, including that she may have become lost, suffered an accidental fall, encountered wildlife, or been the victim of foul play. None of those theories have ever been confirmed. While some later reports have mentioned that a camera lens or lens cap may have been recovered during the search, that information has not been consistently documented in the original investigative records. Stacy's family did not believe she had run away, and there have been no verified sightings of her since the day she disappeared.

More than four decades later, Stacy Arras's disappearance remains one of Yosemite National Park's longest-running unsolved missing person cases. Despite renewed public interest and the release of historical National Park Service investigative files, no evidence has been found to explain what happened to her.

Anyone with information about Stacy Arras's disappearance is encouraged to contact the National Park Service Investigative Services Branch at (209) 379-1992.