Sesiwn Fawr Dolgellau are celebrating their 25th anniversary in 2017.
The festival was established in 1992 by a small group of volunteers that wanted to form a music festival in the town of Dolgellau. The aim was to create a free entry festival that took place on the streets of the town. The idea latched on to the general public and within a few years Sesiwn Fawr Dolgellau had grown into one of Wales’ biggest festivals.
From 2002 until 2008, Sesiwn Fawr Dolgellau was held on the Marian Mawr, a large grassy area next to Afon Wnion. It was during this period that Sesiwn Fawr reached its peak audience figures with sell out crowds of approximately 5,000 attending each year, however, in 2011, Sesiwn Fawr returned on a smaller scale than the 2002–08 Sesiwn Fawr and far closer to its early 1990s roots.
Since 2012, Sesiwn Fawr has returned to Eldon Square, the festival's spiritual home, introducing bands from Wales, Brittany, Ireland, Scotland and England.
In the past, the line-up has included Super Furry Animals, Steve Earle, The Dubliners, Iwcs a Doyle, Burning Spear, Bob Geldof, Saw Doctors, Bryn Fôn, Meic Stevens, Geraint Jarman a'r Cynghaneddwyr, Derwyddon Dr Gonzo, Grupo Fantasma, Paul Dooley, N'Faly Kouyate, Endaf Emlyn, Cerys Matthews and Goldie Lookin Chain.