Ardcarn Mound is a mound and ringfort and National Monument located in County Roscommon, Ireland.LocationArdcarn Mound is located about 6km east of Boyle and 3km south of Lough Key.History and descriptionArdcarn Mound is a bowl barrow. Immediately to the west of this is a trivallate ringfort with souterrain, and to the south of that is a simple rath.