Ruin of Abbey of St Mary is a Grade I listed building in the Gwynedd local planning authority area, Wales. First listed on 19 October 1971. A C13 (E lancet datable to C13) Abbey ruins.

Ruin of Abbey of St Mary

WRENN ID
open-parapet-peregrine
Grade
I
Local Planning Authority
Gwynedd
Constituency
Dwyfor Meirionnydd MP: Liz Saville Roberts (PC)
Country
Wales
Date first listed
19 October 1971
Type
Abbey ruins
Address
Ruin of Abbey of St Mary, Yr Enlli / Bardsey Island, Aberdaron
OS grid reference
SH 120 221
Coordinates
52.76434, -4.78771
Source
Cadw listing

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

Description

The ruin of the Abbey of St Mary features a tower constructed from rubble stone with some sandstone dressings. The tower has a square plan measuring approximately 5.8 meters internally, with walls that survive to a maximum height of about 8 meters at the northwest corner. Originally, there was an entry from the south and a single lancet window on the east side, which has mostly been robbed but is still datable to the 13th century. The second stage of the tower is indicated by a band, and there is a lancet window on the north side. The large opening on the west side appears to be a later alteration. The walls are inset for a first floor located about 4.9 meters above the ground, and the inner dressings of the east lancet window are nearly complete.

Local climate

Ruin of Abbey of St Mary sits in one of the wettest parts of the UK, with an average of 1,410 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 99% of listed buildings.

It averages fewer than one freeze-thaw cycle a year. Average temperatures at this location have risen by 0.2°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.

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Nearby listed buildings

  1. Memorial Cross in graveyard centre Grade II 9 m
  2. Walled Enclosure to Newborough Cross Grade II 13 m
  3. Newborough Cross Grade II 14 m
  4. Graveyard Wall to Abbey of St Mary Grade II 17 m
  5. Memorial Cross in graveyard to S Grade II 18 m
  6. Double Farm-court to Hendy/Ty Nant and Ty Bach/Ty Nesaf. Grade II 26 m
  7. Hendy and Ty Nant Grade II 28 m
  8. Boundary Walls to Hendy and Ty Nant Grade II 37 m
  9. The Chapel Grade II 63 m
  10. Walls to Chapel and Ty Capel Grade II 64 m