Marathon is a census-designated place in Brewster County located along the Southern Pacific railway at the intersection of U.S. Highways 90 and 385. The site was founded during the construction of Galveston, Harrisburg, and San Antonio Railway. The railway constructors reached this area in 1882, but by then, the area had a few settlers. Mayer Halff and Solomon were among the first settlers of this area. The two brothers established their Circle Dot Ranch close to Pena Colorado Springs. In 1882, Capt. E. Shepard, a former sea captain, and a railroad surveyor, bought land in this area. Shepard later founded a post office in 1883 and named the area Marathon after the Plains in Marathon, Greece.