Clannad was formed in 1970 by siblings Ciarán Brennan, Pól, and Máire Brennan and their twin uncles Noel and Pádraig Duggan. The five grew up in Dore, an area of Gweedore, a remote parish in County Donegal in the northwest corner of Ireland. It is a Gaeltacht region where Irish is the main spoken language. Raised as a Roman Catholic family of musicians, the Brennans' mother, Máire "Baba" Brennan (née Duggan), was a music teacher while their father, Leo Brennan, was a member of the Slieve Foy Band, an Irish showband. Later in their careers the two bought and ran Leo's Tavern, a pub in nearby Meenaleck where the Duggan and Brennan children would perform covers of songs by the Beatles, the Beach Boys, and Joni Mitchell.
The band adopted the name Clann as Dobhar, Irish for 'Family from Dore', when they entered a local music competition, and they used that name until 1973. The Brennans' and Duggans' interest in traditional Irish music reached beyond their native Gweedore,[clarification needed] and they performed elsewhere including Tory Island, off Donegal's coast. Armed with some 500 Gaelic songs, they would later begin to arrange these songs for a full band.