[Ir. gleann na smól, valley of the thrushes].
Valley at the headwaters of the River Dodder in south Co. Dublin extending into Co. Wicklow, especially rich in Fenian associations. Oisín first fell to earth here on his return from Tír na nÓg. The proximity to Dublin may explain the glen's frequent citation in romantic, nationalist Irish poetry; see W. H. Drummond, ‘The Lay of Glennasmol’, in Ancient Irish Minstrelsy (Dublin, 1852), 61–79.