Early Irish History and Antiquities and the History of West Cork
RATH.—This term applies to the mound on which a royal residence or that of a chief was situated. Thus we have Rath-na-Riogh, Rath Grainae, Rath Laghaire, all seats of royalty; also Rath of Doon Patrick, another royal residence; Naas Rath, seat of Kings of Leinster.
Dr. Joyce states that 1,100 townlands commence their names with the prefix rath or ra.