Downsville is an unincorporated community and census-designated place (CDP) in southwestern Washington County, Maryland, United States. Its population was 355 as of the 2010 census. It is located southeast of Williamsport on Maryland Route 63 and on Maryland Route 632, southwest of Hagerstown. It is officially included in the Hagerstown Metropolitan Area (Hagerstown-Martinsburg, MD-WV Metropolitan Statistical Area).