Mapping Mountains – Hill Reclassifications – The 500-Metre Tops of Ireland and The 400-Metre Tops of Ireland

Common Mountain (G 709 859) - 500m Top reclassified to 400m Top

There has been a reclassification to the list of The 500-Metre Tops of Ireland and The 400m-Metre Tops of Ireland, with the summit height and its location and the status of the hill confirmed by a Trimble GeoXH 6000 survey conducted by Martin Critchley on the 13^th November 2019.

Sharron Schwartz and Martin Critchley at the summit of Common Mountain.  Photo: Simon Stewart

The criteria for the two listings that this reclassification applies to are:

The 500-Metre Tops of Ireland – Irish hills at or above 500m and below 609.6m (2000ft) in height that have 30m minimum drop.  The list is co-authored by Michael Dewey and Myrddyn Phillips and is published on DoBIH.

The 400-Metre Tops of Ireland – Irish hills at or above 400m and below 500m in height that have 30m minimum drop.  The list is authored by Myrddyn Phillips and two versions of it are published on DoBIH.

The name the hill is listed by is Common Mountain (Sliabh Chamáin) and it is adjoined to Donegal hills which are situated in the north-western part of Ireland (Region 45, Section 45C), and it is positioned with the N56 road to its east and a minor road to its north-west, and has the town of Ardara towards the north north-east and the town of Killybegs towards the south.

When the original list of Irish 500m hills was compiled this hill was listed with a 501m summit height, based on the spot height adjoined to a triangulation pillar that appears on the Ordnance Survey of Ireland 1:50,000 Discovery map 10.

Extract from the OSI 1:50,000 Discovery map 10

Therefore, the reclassification of this hill from the The 500-Metre Tops of Ireland list is due to a Trimble GeoXH 6000 survey conducted by Martin Critchley, resulting in a 499.7m summit height.  As this is below the minimum height required for 500m status the hill is reclassified to the The 400m-Metre Tops of Ireland list.

This now brings the overall total for The 500-Metre Tops of Ireland to 200 and the Subs for this list have increased by two compared to when the list was first published on DoBIH.

Thanks to Jim Bloomer for bringing this survey result to our attention.

The full details for the hill are:

Group:  Donegal

Name:  Common Mountain (Sliabh Chamáin)

OSI 1:50,000 map:  10

Summit Height:  499.7m (Trimble GeoXH 6000)

Summit Grid Reference:  G 70918 85943 (Trimble GeoXH 6000)

Col Height:  c 181m (interpolation)

Col Grid Reference:  G 646 882 (interpolation)

Drop:  c 319m (Trimble GeoXH 6000 summit and interpolated col)

Michael Dewey and Myrddyn Phillips (May 2020)