Fourteenth century financial accounts for the lordship of Ogmore refer to 'a fulling mill next to the castle' (iuxta castrum de Oggemore) (1). The mill was at farm for 20s. It does not appear to have survived into the post-medieval period and no physical traces have been identified.
The accounts, in recording the leasing of meadow in the general area of the castle in 1381-2, refer to `the eastern mill?, confirming the presence of two mills in that area, one of which was Ogmore Mill (a corn mill, NPRN 414222), 0.75 km upstream from the castle. Presumably the 'western' mill was the fulling mill, nearer the castle, though this cannot be confirmed. The given NGR lies on the east side of the castle but the mill's precise location in relation to it is unknown.
The castle was badly damaged in the period 1402-05 during the Glyndwr Revolt. The record of repairs made during the fifteenth century makes no mention of a fulling mill (2).

(1) NA, DL 29/592/9444 & DL 29/592/9445 Lordship of Ogmore ministers' accounts, 1363-4 & 1381-2.
(2) Glamorgan Inventory, Early Castles (1991), p.276

David Leighton, RCAHMW, 14 July 2011