Three defended settlements stand in parallel.... here upon the beautiful Welsh/English - or should that be English/Welsh? - border, not far from Shrewsbury... Ha! Merely lines upon maps, methinks.
According to our friends at Coflein, the central site is:
'A roughly sub-oval enclosure, c.56m N-S by 54m, set n a S facing hillside, c.240m SE of the Breiddin Hillfort (Nprn141162) defined by one or two lines of widely spaced collapsed stone ramparts, 106m N-S by 78m overall.
The enclosure has been associated with the field system (Nprn306995) between it and the Breiddin fort. Excavation, 1933-5, produced RB material, late 1st-4th c. [J.Wiles 12.11.2002]'