Amherstdale is a census-designated place in Logan County, West Virginia, United States, situated along Buffalo Creek. The CDP includes the unincorporated communities of Amherstdale, Becco, Fanco, and Braeholm. The CDP population was 350 as of the 2010 census. Prior to 2010, Amherstdale was part of the Amherstdale-Robinette CDP. Amherstdale has a post office with ZIP code 25607.Amherstdale was also affected by the Buffalo Creek flood disaster which killed, injured, and left thousands homeless.