Mapping Mountains - Hill Reclassifications - The 500-Metre Tops of Ireland

The 500-Metre Tops of Ireland – Hill Reclassifications

The 500-Metre Tops of Ireland are the Irish hills at or above 500m and below 609.6m (2,000ft) in height that have a minimum drop of 30m.  Accompanying the main P30 list are three sub lists; these are the 500m Subs, 490m Subs and the 490m Double Subs with their criteria detailed in the respective Change Registers which are linked in their above titles.

The list is co-authored by Michael Dewey and Myrddyn Phillips and the posts that have appeared on Mapping Mountains detailing the additions, reclassifications and deletions to the main P30 list and the sub lists appear below presented chronologically in receding order.

Mapping Mountains - Hill Reclassifications - The 500-Metre Tops of Ireland

Corcóg (Corcogemore) (L 952 491) – 500m Top deletion (4th reclassification)

There has been a deletion to the list of The 500-Metre Tops of Ireland, with the summit height and its location and therefore the status of the hill confirmed by a survey conducted by Bluesky.

The criteria for the list that this deletion 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 Haroldstreet.

The 500-Metre Tops of Ireland by Michael Dewey and Myrddyn Phillips

The name the hill is listed by is Corcóg (Corcogemore) and it is adjoined to the Maumturk Mountains which are situated in the western part of Ireland (Region 47, Section 47C), and it is positioned with the N59 road to its south and the R336 road to its east, and has the town of Cliften towards the west.

When the original list of Irish 500m hills was compiled this hill was listed with a 609m summit height, based on the spot height that appears on the Ordnance Survey of Ireland 1:50,000 Discovery map 45.

Extract from the Ordnance Survey of Ireland 1:50,000 Discovery Series map

When the list was re-assessed for publication on the DoBIH and the Hill Bagging website this hill was listed with 223m of drop, based on the 609m summit spot height and a col height of 386m, with the latter based on the spot height that appears on the Harvey 1:30,000 Superwalker Connemara map.

Since this re-assessment Corcóg (Corcogemore) has been surveyed by Bluesky.  For Ireland Bluesky have created a national dataset based on photogrammetric survey using Vexcel cameras, creating a 1m DSM and 5m DTM product.  The accuracy given for these is +/- 0.50m for the DSM with directly recorded points with no interpolation, and +/- 1m for the DTM with some interpolation.  The result produced by the Bluesky survey gives this hill a 611.1m summit height.

Bluesky generated image of the summit of Corcóg

Therefore, the deletion of this hill from the The 500-Metre Tops of Ireland list is due to a survey conducted by Bluesky, resulting in a 611.1m summit height.  As this is above the 2,000ft (609.6m) height the hill is reclassified to the The Hewitts of Ireland list.

The full details for the hill are:

Group:  Maumturk Mountains

Name:  Corcóg (Corogemore)

OSI 1:50,000 map:  45

Summit Height:  611.1m

Summit Grid Reference:  L 95262 49137

Col Height:  386m (spot height)

Col Grid Reference:  L 943 496 (spot height)

Drop:  225m

Thanks to:

Kieron Gribbon of The Ireland Walking Guide website who raised the potential of this hill being a new Irish Hewitt based on the 611m summit spot height that appears on the Connemara Mountains map recently published by EastWest Mapping.

Barry Dalby at EastWest Mapping for confirmation of the source of their height data, and relevant details giving accurate height and co-ordinates.

Robert Loughran at Bluesky for detailed analysis of their surveying technique, including accurate heights and contours.

Extract from the EastWest Mapping Connemara Mountains map

For the additions, reclassifications and deletions to The 500-Metre Tops of Ireland list reported on Mapping Mountains since the June 2011 publication of the list by DoBIH and the Hill Bagging website please consult the following Change Registers:

The 500-Metre Tops of Ireland

The 500-Metre Tops of Ireland – The Irish 500m Subs

The 500-Metre Tops of Ireland – The Irish 490m Subs

The 500-Metre Tops of Ireland – The Irish 490m Double Subs

Michael Dewey and Myrddyn Phillips (December 2020)

Mapping Mountains - Hill Reclassifications - The 500-Metre Tops of Ireland

Common Mountain (G 709 859)  500m Top reclassified to 400m Top (3rd reclassification)

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)

Mapping Mountains - Hill Reclassifications - The 500-Metre Tops of Ireland

Pigeon Rock Mountain North Top (J 261 250) - 500m Subs addition (2nd reclassification)

There has been a reclassification to The 500-Metre Tops of Ireland list due to a re-assessment of information on Ordnance Survey of Northern Ireland maps.  This is the second reclassification to this list since its data were re-evaluated for publication on the Database of British and Irish Hills (DoBIH).  The hill is situated in the central western part of the Mourne Mountains in the north-east of Ireland, and is positioned between the small communities of Hilltown to its north-west and Attical to its south.

Access to the hill can be gained from its easterly side where car parking near to the high point of the B27 road gives relatively easy access up its easterly flank; otherwise a more challenging walk can take in this hill whilst visiting a number of adjacent peaks following the course of the Mourne wall.

The hill is named Pigeon Rock Mountain North Top and its summit is positioned at J 261 250.  The south top of this hill is currently listed as Pigeon Rock Mountain with a 534m high summit at J 264 244 with 141m of drop.  Pigeon Rock Mountain North Top was not included in the Sub list that accompanied the main list when published on D0BIH as debate on its prominence favoured c 19m, however this has been re-assessed and detail from a number of Ordnance Survey of Northern Ireland maps have been examined, the details appear below:

OS historic map:  1749ft (530m converted to current datum) for north top and 1755ft (532m converted to current datum) for south top

Map 29:  534m for north top, no spot height for south top.

Harvey map:  534m for north top and 534m for south top.

Mourne Country Outdoor Pursuits map (OS of NI publication 1990):  533m for north top and 534m for south top.

Mournes Activity map (OS of NI publication [update from the Outdoor Pursuits map] 2009):  534m for north top and 534m for south top.

After re-assessment of the above data we have decided to include Pigeon Rock Mountain North Top as a new Sub adjoined to the main 500-Metre Irish list.

This now brings the overall total for The 500-Metre Tops of Ireland to 201 and the Subs have increased by two compared to when the list was published on DoBIH.

Thanks to Jim Bloomer for supplying historical map information and suggesting this hill’s re-assessment.

To access the list on DoBIH.

The full details for the hill are:

Cardinal Hill:  Slieve Donard

Summit Height:  534m

Name:  Pigeon Rock Mountain North Top

OS of NI 1:50,000 map:  29

Summit Grid Reference:  J 261 250

Drop:  c 20m

Michael Dewey and Myrddyn Phillips (August 2016)

Mapping Mountains - Hill Reclassifications - The 500-Metre Tops of Ireland

Knocknaveacal North Top (V 744 526) - 500m Top reclassified to 500m Subs (1st reclassification)


There has been a reclassification to The 500-Metre Tops of Ireland list due to a Trimble survey conducted by John Fitzgerald.  This is the first reclassification to this list since its data were re-evaluated for publication on the Database of British and Irish Hills (DoBIH).  The hill is situated in the western lands of the Beara Peninsula in the south-west of Ireland, and is positioned south-west of the small community of Lauragh and eastward of Ardgroom.

These details are retrospective as the Trimble GeoXH 6000 survey conducted by John Fitzgerald that resulted in the reclassification of this hill from the main 500-Metre P30 list to the 500-Metre Sub-List was conducted on 30^th May 2015 in a rainstorm and fog.

Access to the hill can be gained from its easterly ridge that ascends over the 356m top of Cummeennahillan, or an extended circuit can be combined over the hills of Lackabane (Leaca Bhan), Eskatarriff East Top, Easkatarriff (Eisc an Tairbh), Coomacloghane (Com an Chlochain), Tooth Mountain (Cnoc na bhFiacal), Knocknaveacal South Top and finally Knocknaveacal North Top.

The hill is named Knocknaveacal North Top and its summit is positioned at V 744 562.  The hill was listed with c 31m of drop based on a 513m summit spot height and an estimated col height of c 482m.  To the immediate south of this hill is another hill that is given a 513m spot height on OSI maps, this southern top is included in the 500-Metre Sub-List with c 29m of drop and is named Knocknaveacal South Top.  When re-evaluating data for this list’s publication by DoBIH these two hills proved of interest as they could have been listed as either two qualifying P30s, one twin top P30, one qualifying P30 and one Sub (either way round), or one twin top Sub.

The survey by John Fitzgerald with the Trimble GeoXH 6000 resulted in a 509.1m summit height and a col height of 482.6m at V 74321 56081.  The dramatic decrease in summit height from the 513m map height to the 509.1m surveyed height and the surveyed col height of 482.6m gives this hill a drop value of only 26.5m.

This now brings the overall total for The 500-Metre Tops of Ireland to 201, please click {here} to access the list on DoBIH.

The full details for the hill are:

Cardinal Hill:  Hungry Hill

Summit Height:  509.1m

Name:  Knocknaveacal North Top

OSI 1:50,000 map:  84

Summit Grid Reference:  V 74439 56269

Drop:  26.5m

Michael Dewey and Myrddyn Phillips (November 2015)