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Castell Crwn

Also known as, or recorded in historical documents as;
Llanrhwdrys; Castell Rhonyn

In the community of Cylch-y-Garn.
In the historic county of Anglesey.
Modern authority of Anglesey.
Preserved county of Gwynedd.

OS Map Grid Reference: SH33199083
Latitude 53.38789° Longitude -4.50980°

Castell Crwn has been described as a probable Timber Castle.

There are earthwork remains.

This site is a scheduled monument protected by law.


An oval earthwork enclosure set on low lying ground. Possibly a medieval castle, although it could be a prehistoric settlement enclosure. The enclosure is about 27m north-south by 22m. It is enclosed by a rampart and ditch with a counterscarp remaining on the north-west. There is an east-facing entrance gap. The 4.0-5.0m wide ditch may originally have been a water filled moat. (Coflein–John Wiles 13.08.07)

The monument comprises the remains of a circular earthwork comprising a bank, external ditch and remains of counterscarp bank, with an internal diameter of 24 -25 m. It is situated in a slight depression 20 m E of a small stream flowing N to the sea. The defences are best preserved on the W side, where there is an outer bank 0.3-0.5 m high, a fall to the bottom of the ditch of about 1 m and then a climb of 2 m to the top of the internal bank. The internal bank lies between 0.75 and 1.5 m above the level of the interior. The ditch has been filled in on the E and NE sides, but is still just visible. It is possible that the ditch was filled with water from the adjacent stream. A modern field bank cuts through the S part of the site, causing some damage to the banks. The site is generally better preserved S of this wall, although parts of it are very overgrown with thorn and bramble. A 2 m gap in the interior bank on the E side may represent the original entrance. A shallow gully, possibly a modern drain, runs from the N side of the site. The remains of a bank can be seen in the undergrowth S of the field wall and 10 m W of the outer bank. Its purpose or extent could not be determined. (Scheduling Report)
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Sources of information, references and further reading
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The bibliography owes much to various bibliographies produced by John Kenyon for the Council for British Archaeology, the Castle Studies Group and others.
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This record last updated 05/07/2016 10:41:13