Ballaghaderreen (Irish: Bealach an Doirín) is a town in County Roscommon. It is located on the N5 National primary road. The town has become a bottleneck on the N5 route in recent years and the opening of the Charlestown bypass down the road has exacerbated the problem. The Irish meaning of the town name is 'The way (Bealach) of the little oak (Doirín)'.