Gwynedd Archaeological Trust
Regional Historic Environment Record

Castell Crwn Ringwork, Llanrhwydrys

Primary Reference Number (PRN) : 3515
Trust : Gwynedd
Community : Cylch-y-Garn
Unitary authority : Ynys Mon
NGR : SH33199083
Site Type (preferred type first) : MEDIEVAL RINGWORK
Status : Scheduled Monument

Description :
Castell Crwn, Llanrhwydrys - small motte without a bailey. Castell Crwn is sited 1 3/4m SE of the parish church of St. Rhwydrys. It is a circular earthwork of single bank and ditch in swampy ground near a stream and within the 100ft contour. Diameter is 87ft from crest to crest of the bank and the bank is 4-5ft high above the area. Outside is a wide ditch, for the most part shallow and nearly ploughed out on the NE, best preserved on the W where it holds water. Overall width of bank and ditch is about 35ft. A narrow gap in the bank on the E may be the original entrance, but there is no causeway. The ditch was probably intended to hold water and on the OS the site is shown as an island surrounded by water diverted from the stream. Probably a C12th timber castle. It is in fair condition, overgrown with gorse on the E and W and cut across by a field wall on the S. The bank is in good condition. (RCAHMW, 1937)

Castell Crwn (LB) labelled Castell Rhonyn and changed to Castell Crwn on OS map 1963. <4>

In fair condition but partly overgrown. <5>

Castell Crwn, a circular earthwork at SH 33199083, 30.0m in diameter with an outer ditch. An outer bank is clearly visible on the SW but on the NE it has been destroyed. An E entrance is probably modern. The partly filled ditch is 2.3m deep and the inner rampart 0.6m high. A probable ring-motte. Published survey 25" revised. <6>

Not visited. (Smith, 2005)

Sources :
Cooke, N. , 2014 , Rhyd-y-Groes Repower, Anglesey: Cultural Heritage Assessment. ( © Wessex Archaeology)
Hadley, A. , 2016 , Proposed Wind Turbine at Nant-y-fran, Cemaes, Isles of Anglesey. Cultural Heritage Impact Assessment. ( © Archaeology Wales)
Smith, G. , 2003 , Prehistoric Defended Enclosures: Scoping for Pan-Wales Assessment ( © GAT)
Smith, G. , 2005 , A Survey of Prehistoric Defended Enclosures in North West Wales 2004-2005: West Conwy, Gwynedd (Arfon) & Anglesey ( © GAT)
Smith, G. , 2008 , Iron Age Settlements in Wales: Cadw Defended Enclosures Publication Hillforts and Hut Groups in North-West Wales ( © GAT)
The Royal Commission on the Ancient and Historical Monuments of Wales , 1937 , An Inventory of the Ancient Monuments in Anglesey
Waddington, K. , 2010 , Early Celtic Societies in North Wales
Waddington, K. , 2013 , The Settlements of Northwest Wales: From the Late Bronze Age to the Early Medieval Period
Ordnance Survey , 1963 , SH39SW , <4>
Ordnance Survey , 1967 , SH39SW 3 , <5>
Ordnance Survey , 1969 , SH39SW 3 , <6>

Events :
40621 : Prehistoric Defended Enclosures in North-west Wales, 2004-5: West Conwy, Gwynedd (Arfon) and Anglesey (year : 2005)
44557 : Early Celtic Societies in North Wales (year : 2010)
45013 : Rhyd-y-Groes Repower, Anglesey: Cultural Heritage Assessment. (year : 2014)
45042 : Iron Age Settlements in Wales: Cadw Defended Enclosures Publication. Hillforts and Hut Groups in North-West Wales. (year : 2008)
40620 : Prehistoric Defended Enclosures: Scoping for Pan-Wales Assessment (year : 2003)
45130 : Proposed Wind Turbine at Nant-y-fran, Cemaes, Isle of Anglesey. Cultural Heritage Impact Assessment. (year : 2016)

Related records
National Monuments Record Wales NPRN 95544 https://coflein.gov.uk/en/site/95544/

Compiled date : 31-03-2000


Images :



The above data are supplied by GAT in partnership with its Local Authorities (Anglesey, Conwy and Gwynedd County Councils, and Snowdonia National Park Authority), © GAT 2025 (and in part © Crown, 2025 - as indicated)
This information is supplied for the purposes of personal interest only and may not be used as part of a commercial project.

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