This is a roughly square levelled platform, about 110-120m across, thought to be the parade ground associated with the Roman fort (NPRN 95476). The perimeter is well preserved on the north-east, south-east and south-west sides, taking the form of a prominent scarp or embankment on the last two sides. There are platforms and hollows on the north-eastern side and at the eastern angle. Whilst some of these might be quarry pits others may mark the position of buildings and other features associated with the parade ground. The south-western part of the interior is still reasonably level, but the north-eastern part has been disturbed, presumably for cultivation. A relatively modern road cuts across the platform from north to south.
Some 50m beyond the parade ground's south-east side are the earthworks of a remarkable monumental structure (NPRN 89403). This has been identified as a tribunal or reviewing platform. A small amphitheatre or arena lies a similar distance to the north (NPRN 95666).
Away from Tomen-y-Mur parade grounds are only known in Wales & the borders at the legionary fortresses of Chester and Caerleon (NPRN 275996). At all three sites amphitheatres, equally rare, are also present. It seems reasonable to suppose that the parade grounds and arenas were part of unified ceremonial or religious complexes.

John Wiles 03.03.08