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Magazine at Fort Williamsburg

A Grade II* Listed Building in Llandwrog, Gwynedd

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Latitude: 53.0709 / 53°4'15"N

Longitude: -4.3002 / 4°18'0"W

OS Eastings: 245992

OS Northings: 355103

OS Grid: SH459551

Mapcode National: GBR 5G.BKXC

Mapcode Global: WH43S.X2HL

Entry Name: Magazine at Fort Williamsburg

Listing Date: 29 May 1968

Last Amended: 30 September 1999

Grade: II*

Source: Cadw

Source ID: 20465

Building Class: Defence

Location: Situated immediately beside the Tower near the north-west corner of Fort Williamsburg, approximately 0.5km south-east of the house. Reached via a tunnel passage from the Parade Ground.

County: Gwynedd

Community: Llandwrog

Community: Llandwrog

Locality: Glynllifon

Traditional County: Caernarfonshire

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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 magazine is likely to have been one of the original buildings at the Fort; modern restoration.


Circular rubble stone structure with flat roof set below a mound as a baffle. To north-west is a pointed arched doorway with brick voussoirs below a stone plaque inscribed 'Magazine'. On the other side are steps up to a viewing platform.

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


Vaulted with brick floor.

Reasons for Listing

Listed grade II* as an integral part of this rare and remarkable British example of an C18 private fortification.

Group value with other listed items at Fort Williamsburg.

Other nearby listed buildings

  • II* Tower at Fort Williamsburg
    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
  • II* Tunnel Passage at Fort Williamsburg
    On the northern side of the Fort linking the former Parade Ground and the Tower and beyond to the outer bastions. Fort Williamsburg is approximately 0.5km south-east of the house.
  • II* Gatehouse at Fort Williamsburg
    Built into the bank on the north side of the fort accessed from the main north entrance via a footbridge across the ditch; faces into the former parade ground. Fort Williamsburg is approximately 0.5k
  • II* Armoury at Fort Williamsburg including attached screen walls
    Facing into the former parade ground and backing onto the Barracks at the south-east corner of Fort Williamsburg which is situated approximately 0.5km south-east of the house.
  • II* Barracks at Fort Williamsburg
    At the south-east corner of Fort Williamsburg which is situated approximately 0.5km south-east of the house
  • II* Outer Defensive Wall to Fort Williamsburg
    Forming a perimeter to the fort which is approximately 0.5km south-east of the house and reached by the south drive.
  • II Cascade at Glynllifon
    Facing the main east vista approximately 300m from the house on the south side of the Afon Llifon dingle at the point where it turns north-eastwards.
  • II The Mill Folly Grotto including stone bridge, south of the Afon Llifon
    Situated approximately 200m east of the house, on the south side of the valley of the Afon Llifon.

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