Other branches of the clan: MacSweeney, Sweeney, Sweeny, MacSweeny, MacSwiney, Swiney, Sweney. Swine, Sweny, Sevnagh.
Irish Clan Name: MacSuibhne, MacQueen from Scots Gaelic.

Sweeney is one of the sixty most commonly-found names in Ireland. It occurs with almost the same frequency in the Irish Provinces of Leinster, Connacht and Munster, but less frequently in Leinster. In County Donegal (of which the Irish name is Dún na Gall), this name is the sixth most commonly found in a modern census (50 births of that name in 1921), and ninth in the seventeenth century (46 births of that name in 1659). It is usually contended that the MacSweeneys descent is from the Gall-Gaedhael, of combined Scottish and Viking origins. The Irish word "Gall" means "foreigner", hence the placename Dun na Gall meaning "Fort of the Foreigners".

Ballyorgan is part of the ancestral home of the McSweeneys and forms a stage of the Beara-Breifne Greenway which is based on the historic march of O'Sullivan Beara in 1603.