Trenny accompanied 40 of her classmates from Knoxville, Tennessee on a field trip to Great Smoky Mountains National Park. The students were hiking to Andrews Bald on the trip and separated into small groups when they arrived at the trails. Trenny apparently hiked with several different sections of her classmates at different paces during the day. She was last seen at approximately 3:00 p.m. near Clingman's Dome, walking on a moderately steep trail with sharp drop-offs and dense undergrowth on both sides. Extensive searches of the park continued until the end of October 1976, but Trenny has never been located. She was a sophomore at Bearden High School at the time of her disappearance. Last seen wearing a blue blouse, a blue and white striped sweater, a borrowed brown plaid heavy jacket, blue jeans, blue Adidas shoes and a diamond and star sapphire ring.