Leo is on Clear Creek near the Wise county line twenty miles southwest of Gainesville in Cooke County. In 1894 a post office was established by Robert Heilman. It was named Leo, "lion," by Dr. Stamper of nearby Era because he believed the community to be "a rather rough place." Settlers had arrived in the area before the Civil War, notably several adult members of the Wiley Jones family. Since it was bypassed by major thoroughfares, the town never grew; in 1990 it had eighty people and no major businesses. In 2000 the population dropped to twenty.