Conlen, on U.S. Highway 54 and the Chicago, Rock Island and Gulf Railway in eastern Dallam County, was founded in 1903. It was named for Capt. J. H. Conlen, a Spanish-American War veteran who supervised the building of the Rock Island tracks from Liberal, Kansas, to Santa Rosa, New Mexico, through Sherman, Dallam, and Hartley counties in Texas. During the 1930s Conlen was noted for its high school girls' basketball team, which was sponsored by the Conlen Mercantile Company and which won the state championship in 1934. The community is allied by geography and trade with Stratford in Sherman County. Conlen survived the disastrous dust bowl years and later revived its grain-based economy with the introduction of irrigation wells. Conlen reported four businesses and a population of 150 in 1940; by 1948 its population had decreased to sixty-two, with three businesses. Conlen's population was reported as sixty-one in 1990 and sixty-nine in 2000.