Arno is one mile west of the Pecos River on State Highway 302 and the Atchison, Topeka and Santa Fe Railway in northeastern Reeves County. The settlement began as one of many promotional townsites in the county early in the twentieth century. An Arno post office was operated from 1907 until 1915; Ola Solman was postmistress. The community had a population of ten and one business in the 1930s. From 1945 until 1949 the population was reported as twenty. By 1950 no population was reported.