Gwynedd Archaeological Trust
Regional Historic Environment Record

Llys Caswallon, Site of, E of Pengorffwysfa

Primary Reference Number (PRN) : 3571
Trust : Gwynedd
Community : Llaneilian
Unitary authority : Ynys Mon
NGR : SH47729202
Site Type (preferred type first) : MEDIEVAL LLYS

Description :
Cadwallon Lawhir was a patron of St. Eilian, and the remains of his palace, Llys Caswallon, near Llaneilian, may still be seen. <1>

(SH 47729202) Llys Caswallon (LB) - site of. <2>

SH 47729202 Several disjointed banks, forming no intelligible pattern, probably represent the remains of Llys Caswallon, but are too fragmentary for classification or survey. Correctly sited on OS 25". <3>

'Llys Caswallon' - could this be the site of a Roman signal station? Low lighting shows walls and platforms of several buildings. Local stories tell of an old lighthouse and masonry existed here until 1900's, when it was removed to enlarge the nearby 'caswallon'. The site commands good views from level ground, a rarity in the area. Marked on maps as an antiquity. <4>

Sources :
Smith, G. & Hopewell, D. , 2010 , Anglesey Coastal AONB: The Ancient Landscape of Mon Archaeology Survey Project ( © GAT)
Williams, T. P. T. , 2012 , Llys Caswallon, Mynydd Eilian , Transactions of the Anglesey Antiquarian Society : 2012 : p. 66-70
Baring-Gould, S. & Fisher, J. , 1908 , Lives of the British Saints , <1>
Ordnance Survey , 1963 , SH49SE , <2>
Ordnance Survey , 1969 , SH49SE 5 , <3>
Sherriff, A. , 1983 , PRN 3571 , <4>
Brooks, I. & Laws, K. , 2010 , Llys Caswallon, Llaneilian, Geophysical Survey , <5>

Events :
42858 : PRN 3571 Gat Site Visit (year : 1983)
44034 : Llys Caswallon, Llaneilian, Geophysical Survey (year : 2010)
44150 : Anglesey Coastal AONB: The Ancient Landscape of Mon Archaeology Survey Project (year : 2010)

Related records
National Monuments Record Wales NPRN 406088 https://coflein.gov.uk/en/site/406088/

Compiled date : 31-03-2000


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)
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March 28, 2025, 9:42 pm - HTML file produced from Gwynedd Archaeological Trust Regional HER
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