|Probable Military Road: ESE (9) to Glenlvce (Dumfries & Galloway)
The only ancient source which names the Rerigonium settlement is Ptolemy's Geography, where the name is listed along with Locopibia as the only two Πολεις within the territories of the Novantae tribe of south-west Scotland. The most striking thing about the name is that the word rigon, Welsh/Gaelic for 'king', occurs in the middle of it. This is preceeded by a pronominal prefix re-, with uncertain meaning, and followed by a common locative suffix denoting a place-name (-ium in Latin, -ιον in original Greek). The whole name may be translated something along the lines of 'The Place of the King'.
Where was this kingly place situated? Luckily, Ptolemy's Geography also records several other geographical features in the lands of the Novantae tribe; the Rhinns of Galloway were known in Roman times as the Novantarum Promontorium, the entire south-western headland as the Novantarum Peninsula and the ancient name of Loch Ryan was the Rerigonius Sinus, or the 'Bay of Rerigonium.' For the ancient town of Rerigonium then, we should narrow down our search to the small coastal inlet whose modern name Ryan, is very-likely derived from the ancient seat of the Novantae kingdom.
There are plenty of ancient and awesome sites situated along both the eastern and western shores of Loch Ryan ...
'In the fifth year of campaigning ... he [Agricola] manned with troops that part of the British coast which faces Ireland ...' (Tacitus Agricola XXIV.i-ii)
It would appear likely that a Roman fort belonging to the early conquest period lies buried somewhere beneath the streets of modern Stranraer. The only physical evidence for this proposed Roman encampment is circumstantial, there being traces of a Roman road leading in the direction of the town from Glenluce in the east-south-east, following the same course as the modern A75. The Romans were not in the habit of creating roads which led nowhere, and it is reasonable to assume that this particular road led to some sort of military establishment on the southern shore of Loch Ryan, perhaps built during the governorship of Gnaeus Julius Agricola in his fifth year in office c.AD81 (see quote above).