Ballaghaderreen (Irish: Bealach an Doirín) is a town in County Roscommon, located on the N5 National primary road. The Irish meaning of the town name is 'The way (Bealach) of the little oak (Doirín)'.
The local Gaelic Athletic Association team plays in the Mayo league and its players represent County Mayo.
In 1860 Ballaghaderreen Cathedral was dedicated as the cathedral for the Roman Catholic Diocese of Achonry.
Prior to 1898 the town and parish of Ballaghaderreen and Edmonstown was located in the eastern part of County Mayo until its transfer to County Roscommon under the Local Government Act 1898 by the Parliament of the United Kingdom.