Ancient hill-fort, the largest in Ireland, on a hilltop near Kilcullen, Co. Kildare, 5 miles ESE of Kildare town. Enclosing an area of 34 acres, Dún Ailinne features a circular wall 450 yards in diameter that is sometimes 15 feet high. Recent excavations show occupation on the site from Neolithic times with traces of Iron Age use; other records indicate use as late as 1800. Dún Ailinne appears to have been the most important royal site in south Leinster until the 7th century, and is now thought to have been the seat of the kings of Leinster. Yet it seems to have been used only in undetermined functions, and was not inhabited in any permanent fashion. The mythical Leinster king Find File is thought to have lived here, and may have given his name to it. The site is popularly known as Knockawlin and Knockaulin. See also CRUACHAIN; EMAIN MACHA; TARA.