Arigna (, formerly Cairn An Ailt), is a village in County Roscommon, Ireland. It is near Lough Allen (on the Shannon-Erne Waterway), on a designated scenic route between Keadue and Sliabh an Iarainn. Arigna is situated in Kilronan Parish alongside the villages of Keadue and Ballyfarnon. The village lies close to the shores of Lough Allen. There is a long association with the mining industry, carried out for over 400 years until the mines closed in 1990.