Persimmon Gap began as a stream valley, but later the stream changed course, leaving the Gap dry. This low pass became a natural trail for native people, including the Comanches, who were fierce raiders from the north. During the full moon of September and after the summer rains, they headed south into Mexico. The raiders returned with captives and livestock. The annual north and south passage of people and livestock created a trampled band of earth known as the Great Comanche Trail.