1. A rather irregular, curvilinear enclosure, about 152m north-south by 84m, tapering to the south, defined by substantial banks, or scarps, having an additional, detached rampart on the east & a possible west-facing entrance: the form of the earthworks suggests that an original, roughly oval enclosure, 70-80m across, was extended to the south. (source: Os495card; SN55SE3).

J.Wiles 14.12.04

2. Castell Allt-goch commands the rounded summit of a knoll set higher than the flatter siting of Castell Goetre beyond. It is an oval hillfort, with opposing east and west gateways and evidence for enlargement from a smaller first phase hillfort. The surviving rampart is impressive in places, standing up to 4m high above the ditch bottom. On the east side low outworks strike through the pasture indicating the position of a once formidable double outer defence. Davies and Hogg writing in 1994 suggested that cultivation had removed the bivallate outer defences around the rest of the fort. This was probably never the case; instead these outworks specifically flank the main east gateway (central indent in long side of hillfort) as a way to baffle and slow approaching visitors.

Castell Allt-goch may originally have looked quite different. On the south-west side there is an increase in the number of quartz blocks incorporated in an adjacent field wall, no doubt sourced from the fort. Around the rampart large walling stones and quartz blocks have tumbled out of erosion scars, while at the western gateway it is possible to make out intact quartz and stone rampart walling. There was clearly a high use of quartz blocks in the rampart for this fort.

Traces of an early-phase rampart crossing the middle of the hillfort, originally identified by Terry James from aerial photographs, suggests the hillfort began as a smaller hilltop enclosure before being more than doubled in size.

Edited from: Driver, T. 2016. The Hillforts of Cardigan Bay. Logaston Press.

T. Driver, RCAHMW, 2016

3. Royal Commission aerial reconnaissance on 9th July 2018, during the 2018 drought, revealed extensive parchmarks of the eastern defences, showing at least one linking ditch between the outworks, the presence of the encircling ditch around the fort and the well demarcated ditch subdividing the fort's interior showing a period of enlargement or contraction of the hillfort. Crucially the parchmarks also revealed a 62m square Roman camp (NPRN 300226) built hard against the defences on the south side, either a remnant of a campaign attack or, perhaps more likely, a practice camp built for training following the abandonment of the hillfort. This is thus the first example in Wales of a Roman camp being found in direct association with an Iron Age hillfort.

T. Driver, RCAHMW, 2023.