Caerau Hillfort is a Cadw Scheduled Ancient Monument (GM018)
1. The Hillfort comprises a triangular, enclosed area 5.1ha., 400m(E-W) by 250m at the base. Bivallate with two entrances, plain overlooked on the S, inturned on the E. The ramparts are generally wooded, with interior pasture, formerly cultivated.
Source: RCAHMW 1976 Glamorgan I.2, 44 .
2. There is a possible castle ringwork set at NE angle (Nprn94518), with a church on its S (Nprn301612)
See also associated medieval settlement ( Nprn15250).
3. In 2011 the Department for Archaeology and Numismatics Amgueddfa Cymru – National Museum Wales along with Cadw and the Royal Commission funded a LiDAR survey of St. Fagans National History Museum and its environs including Ely. This work highlighted the distinctive triangular interior of the hillfort and the steep north and south slopes, both fortified by three massive ramparts with accompanying ditches. Further processing of the LiDAR data resulted in a ‘bare-earth’ digital terrain model, with houses and trees stripped away, revealing the magnificent sculpted ramparts and ditches.