Aughnasurn, or Aghnasurn is a townland in the civil parish of Kilbryan, County Roscommon, Ireland.

Adjoining townlands are Annagh to the south, Bodorragha to the east, Derreenagan to the north and Largan to the west.

[2] Holy Trinity Abbey, founded around 1220 on an island in Lough Key and abandoned in 1606–07, owned property at Aghnasurn and Estersnow.

Other societies in Roscommon were at Castlerea, Fuerty, Elphin, Ballymoe and Dunamon, Knockadoe, Knockgrohery, Kiltoom, Frenchpark, Cappagh, Kilmore, Athlone, Strokestown, Mount-Talbot and Aughram.

[6] A report from the Reverend Dominick Noon on the Parishes of Aughana and Aughnasurn was read in a British parliamentary debate on 23 November 1848.