Caoimhín Ó Raghallaigh (born August 28, 1979) is a fiddler, born in Dublin, Ireland. He is known for developing a drone-based fiddle style heavily influenced by the uilleann pipes and the music of Sliabh Luachra. Ó Raghallaigh spent several summers working part- and full-time in the Irish Traditional Music Archives in Dublin, opening up a wealth of old recordings which influenced his repertoire and style. Together with uilleann piper Mick O'Brien, he recorded Kitty Lie Over, named No.1 Traditional Album of 2003 by Earle Hitchner in the Irish Echo.He performs regularly with West Kerry accordion player Brendan Begley, and has collaborated many times with sean-nós singer Iarla Ó Lionáird. He has also performed with Icelandic group Amiina, Sam Amidon, The Waterboys among others. He is a member of two contemporary traditional music groups: The Gloaming (with Martin Hayes, Iarla Ó Lionáird, Dennis Cahill and Thomas Bartlett) and This Is How We Fly (with Petter Berndalen, Nic Gareiss and Seán Mac Erlaine). He has also worked in theatre, having been commissioned by the Abbey Theatre to write music, and works regularly with Gare St Lazare Players.As well as playing on violin and harganger fiddle, Caoimhín Ó Raghallaigh plays an instrument made by Norwegian luthier Salve Hakedal, a fiddle with five bowed strings and five sympathetic strings, a cross between a harganger fiddle and a five string violin (first made for American hardanger fiddle player Dan Trueman, and commissioned by Caoimhín with the head and tailpiece of Salve Hakedal's Viola d’Amore model). Ó Raghallaigh uses crosstunings or scordatura (common in Norwegian and old-time American fiddling), and uses baroque and transitional bows made by Michel Jamonneau. Ó Raghallaigh also used to play a Viola Pellegrina Pomposa by American luthier David Rivinus, a highly asymmetrical five-string viola. Caoimhín also plays tin whistle, flute and uilleann pipes, having been taught whistle and flute by Co. Clare flautist Michael Tubridy of The Chieftains and Ceoltóirí Chualann.