An Grianán Theatre, Theatre in Letterkenny, Ireland

An Grianán Theatre is a performing arts venue in the center of Letterkenny, with a main auditorium that seats around 380 people and full professional staging equipment. The building also has a studio space for smaller productions and a foyer area used for exhibitions and events.

The theatre was built in the 1990s with public funding and opened in 1999, filling a long-standing gap in the performing arts offer of County Donegal. Since then it has grown into one of the main venues on the northwest Ireland touring circuit.

The name comes from Grianán of Aileach, a prehistoric ring fort in Burt held to date from around 1700 BCE. Each January the theatre partners Letterkenny Trad Week, and each June the Irish Aerial Dance Fest fills it with workshops and performances; it has twice hosted Fleadh Cheoil na hÉireann.

The theatre sits in the heart of Letterkenny and is easy to reach on foot from the town center, with parking available nearby. A café on the ground floor is open on performance days, making it a practical spot to arrive early and settle in before the show.

The theatre is named after Grianán of Aileach, a prehistoric ring fort in Burt believed to date back to 1700 BCE; its Irish name means 'Stony House of the Sun'. In 2007 a Rathmullan graphic design studio won the European Design Award in Athens for its variable design for the theatre. The green room holds a framed T-shirt signed by Glen Hansard of The Frames, declaring it 'the best room in Ireland'.