Castell Gronw, Bala

Has been described as a Certain Timber Castle (Motte)

There are earthwork remains

NameCastell Gronw, Bala
Alternative NamesLlangower; Castell Gronw Bevr o Benllyn
Historic CountryMerioneth
Modern AuthorityGwynedd
1974 AuthorityGwynedd

A mound identified as a medieval castle site, situated on the south bank of the Dee where it leaves Bala Lake. This is a mutilated generally circular mound, roughly 20-23m in diameter and 4.5m high, with a level summit some 9.0m across. There is no trace of a ditch. A curving boundary ditch to the south-west is thought to represent a bailey enclosure roughly 25-35m deep. However, nowhere else in the county has a bailey attached to a castle mound been identified. The name has been linked to Goronwy ab Ednyfed Fychan, steward to Llywelyn ap Gruffudd, who died in 1268. The main castle of Penllyn was across the river at Bala and the status and indeed the very identification of this mound are unclear. (Coflein–John Wiles 10.07.07)

This site is a scheduled monument protected by law

Not Listed

The National Monument Record (Coflein) number(s)
County Historic Environment Record
OS Map Grid ReferenceSH930350
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Photo by Tony Hurst All Rights Reserved
Photo by Tony Hurst All Rights Reserved
Photo by Tony Hurst All Rights Reserved

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  • Morgan, Gerald, 2008, Castles in Wales: A Handbook (Talybont: Y Lolfa Cyf.) p. 241 (listed)
  • King, D.J.C. with Kenyon, J.R., 2001, 'The Castles: a Study in Military Architecture' in Smith J.B. and Smith L.B. (eds), History of Merioneth Vol. 2 p. 414
  • King, D.J.C., 1983, Castellarium Anglicanum (London: Kraus) Vol. 1 p. 277
  • RCAHMW, 1921, An inventory of the Ancient Monuments of Merionethshire (HMSO) p. 131 No. 428 online copy
  • Lewis, Samual, 1849, A Topographical Dictionary of Wales online copy [online copy >]


  • Hogg, A.H.A. and King, D.J.C., 1963, 'Early castles in Wales and the Marches: a preliminary list' Archaeologia Cambrensis Vol. 112 p. 77-124
  • Renn, D.F., 1959, 'Mottes: a classification' Antiquity Vol. 33 p. 106-12