Magazine at Fort Williamsburg is a Grade II* listed building in the Gwynedd local planning authority area, Wales. First listed on 29 May 1968. Military structure.

Magazine at Fort Williamsburg

WRENN ID
dusk-span-sable
Grade
II*
Local Planning Authority
Gwynedd
Constituency
Dwyfor Meirionnydd MP: Liz Saville Roberts (PC)
Country
Wales
Date first listed
29 May 1968
Type
Military structure
Address
Magazine at Fort Williamsburg, Glynllifon, Llandwrog
OS grid reference
SH 459 551
Coordinates
53.07091, -4.30018
Source
Cadw listing

Also on this page: flood risk · radon risk · weather exposure · detailed attributes ↓

Description

The Magazine at Fort Williamsburg is a Grade II* listed circular structure made of rubble stone, featuring a flat roof and situated below a mound that serves as a baffle. To the north-west, there is a pointed arched doorway adorned with brick voussoirs, and a stone plaque inscribed with the word 'Magazine'. On the opposite side, steps lead up to a viewing platform.

The fort itself is roughly square in shape, with redans at each of the four corners, surrounded by ditches and revetment walls. Inside, the Magazine is vaulted and has a brick floor.

Local climate

Magazine at Fort Williamsburg sits in one of the wettest parts of the UK, with an average of 1,370 mm of rain a year. This makes it wetter than 97% of listed buildings in the UK. Its exposure to wind-driven rain is greater than that of 98% of listed buildings.

It experiences an average of 20 freeze-thaw cycles a year, fewer than 78% of listed buildings. Of these, 9 follow at least 1 mm of rain in the preceding 48 hours. Average temperatures at this location have risen by 0.3°C per decade since 1991.

Averages for 1991–2020; temperature trend 1991–2025. Figures describe the wider area (a grid cell of roughly 10 km), not the individual site. Contains modified Copernicus Climate Change Service information 2026.

More on this building

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Nearby listed buildings

  1. Tower at Fort Williamsburg Grade II* 6 m
  2. Tunnel Passage at Fort Williamsburg Grade II* 26 m
  3. Gatehouse at Fort Williamsburg Grade II* 53 m
  4. Armoury at Fort Williamsburg including attached screen walls Grade II* 86 m
  5. Barracks at Fort Williamsburg Grade II* 100 m
  6. Outer Defensive Wall to Fort Williamsburg Grade II* 114 m
  7. Cascade at Glynllifon Grade II 230 m
  8. The Mill Folly Grotto including stone bridge, south of the Afon Llifon Grade II 236 m
  9. Fountain at end of east vista Grade II 251 m
  10. Eastern Cavern north of the path near main east vista fountain Grade II 276 m