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Cof Cymru: National Historic Assets of Wales · Wales

Tower at Fort Williamsburg

Llandwrog, Gwynedd, Wales

The record

Designation
Listed building, Grade II*
Broad class
Defence
Date of designation
29 May 1968
Locality
Glynllifon
Community
Llandwrog
Unitary authority
Gwynedd
Country
Wales
Coordinates
53.07086, -4.30009
Cadw reference
3791

Slide toward Today to fade the historical sheet and see the modern map underneath.

David Rumsey Map Collection, Stanford Libraries

Shown on 5 historical map sheets, the earliest the 1795 "To Sir Watkin Williams-Wynn Bart ... the map of the six counties of North Wales is most humbly inscribed by his obedient humble servant" (Llyfrgell Genedlaethol Cymru – The National Library of Wales).

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This record in Cadw's own full report ↗

Cadw's description

Situated approximately 0.5km south-east of the house and reached by the south drive. The tower is the focal building within the Fort and is built on a mound near its north-west corner, between inner and outer bastions and reached via a tunnel.

Fort Williamsburg was built by Sir Thomas John Wynn in 1761 following his election as MP for Caernarvonshire and his appointment as Constable of Caernarvon Castle and Lord Lieutenant making him responsible for the county's militia. He was a notable eccentric of his day and he carried out these responsibilities in an unparalleled way, by building his own private garrison within the park at the family home.

On the day of George III's coronation (September 1761) Wynn founded 'The Society or Garrison at Fort Williamsburg in Glynllifon Park' and he also created 'The Holy Order of Sisterhood United, Connected and Regulated with the Free, Firm and Friendly Garrison of Williamsburg' - a unique volunteer organisation. The intention was for the garrison to comprise a Commander in Chief, a Governor, Lieutenant-Governor, 100 Officers, an Archdeacon, 24 chaplains, 24 honorary members and an unlimited number of volunteers. Although the officers were not part of the regular army they wore full and colourful uniform all at Wynn's expense.

The Caernarvonshire Militia was mobilised for a year while there was a threat of French invasion but even after the 1763 Treaty of Paris the muster books show that the Williamsburg garrison continued to meet. However, having realised that Fort Williamsburg had limited strategic capability, and with the American War of Independence once again threatening British shores, Wynn began work on Fort Belan begun in 1775.

The tower is said by RCAHMW to be one of the additions made in 1773-76. Further alterations are said to have been carried out between 1832 and 1840. Modern restoration.

The tower is set on a motte-like mound and has wide views across the estate and out to sea. It is a 2-stage octagonal tower built of brick with scribed cement render and has a crenellated parapet and a square vice tower to south. There are band courses above each floor; the 1st floor has replaced semicircular headed horned sash windows and the ground floor has square-headed openings including a doorway to north-west and another to the stair tower. Over the former, main, doorway is a stone plaque inscribed 'Williamsbourg Fort'.

The fort is roughly square with redans to the four corners and with surrounding ditches and revetment walls.

Much restored and without significant individual features. Winding timber stairs rising to single octagonal chamber at 1st floor and on to roof level.

Listed grade II* as a key building within a rare and remarkable British example of an C18 private fortification.

Group value with other listed items at Fort Williamsburg.

Nearby in the register

Other entries of the same register within about three miles of this one, by straight line.

Designated Historic Asset GIS Data, The Welsh Historic Environment Service (Cadw), 2026-09-07, licensed under the Open Government Licence http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/ Cadw, the Welsh Historic Environment Service · Open Government Licence v3.0
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