No / Rerigonium, a place-name in Ptolemy¿s Geography, is thought to have been located in the Rhinns of Galloway, but its site has never been identified. There is a strong circumstantial case for regarding the Innermessan area on the eastern side of Loch Ryan as being the likely locus of Rerigonium. Why is this of interest? It is contended that the name, in both the British and Old Welsh forms, indicates an important function perhaps in the pre-Roman Iron Age in connection with the Novantae, as well as the obscure post-Roman entity known as Rheged.