According the children's parents, the family was walking trails including the Appalachian Trail and the children were walking in front of them.
The parents said they lost sight of the children while returning to a public parking lot on the mountain.
According to authorities, the siblings, who are from Kingsport, Tenn., got lost during the hike and ended up spending more than 12 hours alone.
The U.S. Forest Service said a child's shoe was found about a mile from where they were last seen, leading searchers to the children.
