Thursday 6 June 2019

Mapping Mountains – Hill Reclassifications – Hewitts



Hewitts – Hill Reclassifications

The Hewitts (an acronym for Hill in England, Wales or Ireland over Two Thousand feet high) are all hills in these countries at or above 2,000ft (609.6m) in height that have a minimum drop of 30m, accompanying the main list are two sub category’s entitled SubHewitts, with the two sets of criteria being any hill at or above 600m and below 2000ft (609.6m) in height that has a minimum drop of 30m and any hill at or above 2000ft (609.6m) in height with 20m or more and below 30m of drop.

The listing originated as the Sweats (an acronym for Summits in Wales and England Above Two-thousand FEET) and appeared as The Absolute Summits of England and Wales in The Relative Hills of Britain book published by Cicerone Press in 1992, its author; Alan Dawson then separated the component parts and renamed them the Hewitts and published each in the TACit Tables booklet entitled The Hewitts and Marilyns of Wales (February 1997) and The Hewitts and Marilyns of England (June 1997).

The posts that have appeared on Mapping Mountains detailing the hill reclassifications specifically for this list appear below presented chronologically in receding order.








Mapping Mountains - Hill Reclassifications - Hewitts

Foel Penolau (SH 661 347 and SH 661 348) – Sub-Hewitt reclassified to Hewitt (7th reclassification)


This is one in a series of retrospective Hill Reclassification posts that detail hills whose status has altered in the listing of the Welsh Hewitts (an acronym for Hill in England, Wales or Ireland over Two Thousand feet high).  These reclassification posts will give details of hills where I have direct association with their change of status, and they will tie in with a forthcoming Change Register giving detail to this list and its alterations since first publication.

The listing of Welsh Hewitts was published in booklet format by TACit Tables in February 1997 and entitled The Hewitts and Marilyns of Wales.  This list evolved out of The Absolute Summits of England and Wales which were known as the Sweats (an acronym for Summits in Wales and England Above Two-thousand FEET) and which was published by Cicerone Press in 1992 in the book entitled The Relative Hills of Britain.  The list compiler for the Hewitts and the preceding Sweats is Alan Dawson.

When the Welsh Hewitts list was published in booklet format there were 137 qualifying hills listed with their criteria being any Welsh hill at or above 2000ft (609.6m) in height with 30m minimum drop, accompanying the main list are two sub category’s entitled SubHewitts, with the two sets of criteria being any Welsh hill at or above 600m and below 2000ft (609.6m) in height that have a minimum drop of 30m and any Welsh hill at or above 2000ft (609.6m) in height with 20m or more and below 30m of drop.

The Hewitts and Marilyns of Wales by Alan Dawson

The details for the hill reclassification appear below:

The name of the hill is Foel Penolau, and it is adjoined to the Rhinogydd group of hills, and it is positioned with the A496 road to the west and the A470 road and the village of Trawsfynydd towards the east.

Foel Penolau (SH 661 347 & SH 661 348)

Prior to this hill’s reclassification to Hewitt status it was listed as a Sub-Hewitt with 26m of drop based on the 614m summit spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, with also a 614m twin top appearing on the Ordnance Survey Vector Map Local hosted on the Geograph website which is entitled the Interactive Coverage Map, and the 588m spot height that was considered to be positioned at the bwlch and appears on the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map.

As the contouring on the area of this hill’s bwlch suggested its critical position was nearer the boulder field at the base of this hill’s south-western cliff face it was prioritised for a GNSS survey.

Subsequently the GNSS survey took place on the 17th November 2018 with a more detailed bwlch survey taking place on the 26th November 2018.  The hill was surveyed by Myrddyn Phillips and Aled Williams on the 17th and by Myrddyn Phillips on the 26th using a Trimble GeoXH 6000 to determine the summit and bwlch height and also its drop value, resulting in the following summary:


1st summit survey 17.11.18:  614.379m at SH 66145 34774

2nd summit survey 17.11.18:  614.380m at SH 66184 34832

Bwlch survey 17.11.18:  582.482m at SH 66099 34735

With 1mm difference between the northern and southern summits the Trimble GeoXH 6000 was unable to split these tops.  Therefore, with a surveyed summit height of 614.4m and with a surveyed bwlch height of 582.5m, these values give this hill 31.9m of drop, with these details being forwarded to the list author.

The Trimble GeoXH 6000 set-up position on the northerly summit of Foel Penolau

The reclassification of this hill from Sub-Hewitt to Hewitt status was accepted by the list author and its new classification augmented in to the listing of the Hewitts in November 2018.


The full details for the hill are:

Name:  Foel Penolau

OS 1:50,000 map:  124

OS 1:25,000 map:  18

Summit Height:  614.4m (converted to OSGM15)

Summit Grid Reference:  SH 66187 34835 & SH 66148 34777 (as listed in the Hewitts)

Bwlch Height:  582.5m (converted to OSGM15)

Bwlch Grid Reference:  SH 6609 3473 (as listed in the Hewitts)

Drop:  31.9m


Myrddyn Phillips (July 2019)







Mapping Mountains - Hill Reclassifications - Hewitts

Fan y Big (SO 036 206) – Hewitt reclassified to SubHewitt (6th reclassification)


This is one in a series of retrospective Hill Reclassification posts that detail hills whose status has altered in the listing of the Welsh Hewitts (an acronym for Hill in England, Wales or Ireland over Two Thousand feet high).  These reclassification posts will give details of hills where I have direct association with their change of status, and they will tie in with a forthcoming Change Register giving detail to this list and its alterations since first publication.

The listing of Welsh Hewitts was published in booklet format by TACit Tables in February 1997 and entitled The Hewitts and Marilyns of Wales.  This list evolved out of The Absolute Summits of England and Wales which were known as the Sweats (an acronym for Summits in Wales and England Above Two-thousand FEET) and which was published by Cicerone Press in 1992 in the book entitled The Relative Hills of Britain.  The list compiler for the Hewitts and the preceding Sweats is Alan Dawson.

When the Welsh Hewitts list was published in booklet format there were 137 qualifying hills listed with their criteria being any Welsh hill at or above 2000ft (609.6m) in height with 30m minimum drop, accompanying the main list are two sub category’s entitled SubHewitts, with the two sets of criteria being any Welsh hill at or above 600m and below 2000ft (609.6m) in height that have a minimum drop of 30m and any Welsh hill at or above 2000ft (609.6m) in height with 20m or more and below 30m of drop.

The Hewitts and Marilyns of Wales by Alan Dawson

The details for the hill reclassification appear below:

The name of the hill is Fan y Big, and it is adjoined to the Bannau Brycheiniog group of hills, and it is positioned between the towns of Aberhonddu (Brecon) to its north and Merthyr Tudful to its south.

Fan y Big (SO 036 206)

Prior to this hill’s reclassification to SubHewitt status it was listed as a Hewitt with 30m of drop based on the 719m summit spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and the 689m bwlch spot height that appears on the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map.

As the listed drop value of 30m is the minimum required for Hewitt status it was prioritised for a GNSS survey.  Prior to this survey taking place Aled Williams analysed this hill with LIDAR data resulting in a 716.3m summit height and a 688.1m bwlch height, with these values giving this hill 28.2m of drop.

LIDAR summit image of Fan y Big

Subsequently the GNSS survey took place on the 30th June 2018 with a repeat summit survey taking place on the 21st August 2018.  The hill was surveyed by Myrddyn Phillips using a Trimble GeoXH 6000 to determine the summit and bwlch height and also its drop value, resulting in the following:

1st summit survey 30.06.18:  716.800m

2nd summit survey 30.06.18:  716.676m

3rd summit survey 21.08.18:  716.754m

Bwlch survey 30.06.18:  688.2m

The average of the three summit surveys comes to 716.7m and with a surveyed bwlch height of 688.2m, these values give this hill 28.5m of drop, with all these details being forwarded to the list author.

The Trimble GeoXH 6000 gathering data at the summit of Fan y Big

The reclassification of this hill from Hewitt to SubHewitt status was accepted by the list author and its new classification augmented in to the listing of the Hewitts in July 2018.


The full details for the hill are:

Name:  Fan y Big

OS 1:50,000 map:  160

OS 1:25,000 map:  12

Summit Height:  716.7m (converted to OSGM15, average of three summit surveys)

Summit Grid Reference:  SO 03654 20669 (as listed in the Hewitts)

Bwlch Height:  688.2m (converted to OSGM15)

Bwlch Grid Reference:  SO 037 198 (as listed in the Hewitts)

Drop:  28.5m


Myrddyn Phillips (June 2019)







Mapping Mountains - Hill Reclassifications - Hewitts

Bera Mawr (SH 674 682) – Hewitt reclassified to SubHewitt (5th reclassification)


This is one in a series of retrospective Hill Reclassification posts that detail hills whose status has altered in the listing of the Welsh Hewitts (an acronym for Hill in England, Wales or Ireland over Two Thousand feet high).  These reclassification posts will give details of hills where I have direct association with their change of status, and they will tie in with a forthcoming Change Register giving detail to this list and its alterations since first publication.

The listing of Welsh Hewitts was published in booklet format by TACit Tables in February 1997 and entitled The Hewitts and Marilyns of Wales.  This list evolved out of The Absolute Summits of England and Wales which were known as the Sweats (an acronym for Summits in Wales and England Above Two-thousand FEET) and which was published by Cicerone Press in 1992 in the book entitled The Relative Hills of Britain.  The list compiler for the Hewitts and the preceding Sweats is Alan Dawson.

When the Welsh Hewitts list was published in booklet format there were 137 qualifying hills listed with their criteria being any Welsh hill at or above 2000ft (609.6m) in height with 30m minimum drop, accompanying the main list are two sub category’s entitled SubHewitts, with the two sets of criteria being any Welsh hill at or above 600m and below 2000ft (609.6m) in height that have a minimum drop of 30m and any Welsh hill at or above 2000ft (609.6m) in height with 20m or more and below 30m of drop.

The Hewitts and Marilyns of Wales by Alan Dawson

The details for the hill reclassification appear below:

The name of the hill is Bera Mawr, and it is adjoined to the Carneddau group of hills, and it is positioned with the A55 road and the north Wales coast to its north-west, and has the city of Bangor towards its west north-west.

Bera Mawr (SH 674 682)

Prior to this hill’s reclassification to SubHewitt status it was listed as a Hewitt with an estimated c 30m of drop based on the 794m summit spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and an estimated bwlch height of c 764m.

As the estimated drop value of c 30m is the minimum required for Hewitt status it was prioritised for a GNSS survey and this took place on the 10st March 2014.  The hill was surveyed by Myrddyn Phillips using a Trimble GeoXH 6000 to determine the summit and bwlch height and also its drop value.  The survey resulted in a 793.6m summit height and a 763.9m bwlch height, with these values giving this hill 29.7m of drop, with these details being forwarded to the list author.

The Trimble GeoXH 6000 gathering data at the summit of Bera Mawr

The details for this hill were then analysed via LIDAR by Aled Williams, resulting in a 792.98m summit height and a 764.04m bwlch height, with these values giving this hill 28.94m of drop.

LIDAR image of Bera Mawr

The hill was subsequently surveyed by Alan Dawson using a Leica RX1250 on the 14th June 2017, resulting in a 793.7m summit height and a prioritised bwlch height and position taken from the data previously produced by the Trimble GeoXH 6000 survey and LIDAR analysis. 

The reclassification of this hill from Hewitt to SubHewitt status was accepted by the list author and its new classification augmented in to the listing of the Hewitts in July 2017.


The full details for the hill are:

Name:  Bera Mawr

OS 1:50,000 map:  115

OS 1:25,000 map:  17

Summit Height:  793.7m (converted to OSGM15)

Summit Grid Reference:  SH 67485 68274 (as listed in the Hewitts)

Bwlch Height:  764.0m (as listed in the Hewitts)

Bwlch Grid Reference:  SH 6751 6815 (as listed in the Hewitts)

Drop:  29.7m (as listed in the Hewitts)


Myrddyn Phillips (June 2019)







Mapping Mountains - Hill Reclassifications - Hewitts

Calf Top (SD 664 856) – SubHewitt reclassified to Hewitt (4th reclassification)


This is one in a series of retrospective Hill Reclassification posts that detail hills whose status has altered in the listing of the English Hewitts (an acronym for Hill in England, Wales or Ireland over Two Thousand feet high).  These reclassification posts will give details of hills where I have had direct association with their change of status, and they will tie in with a forthcoming Change Register giving detail to this list and its alterations since first publication.

The listing of English Hewitts was published in booklet format by TACit Tables in June 1997 and entitled The Hewitts and Marilyns of England.  This list evolved out of The Absolute Summits of England and Wales which were known as the Sweats (an acronym for Summits in Wales and England Above Two-thousand FEET) and which was published by Cicerone Press in 1992 in the book entitled The Relative Hills of Britain.  The list compiler for the Hewitts and the preceding Sweats is Alan Dawson.

When the English Hewitts list was published in booklet format there were 178 qualifying hills listed with their criteria being any English hill at or above 2000ft (609.6m) in height with 30m minimum drop, accompanying the main list are two sub category’s entitled SubHewitts, with the two sets of criteria being any English hill at or above 600m and below 2000ft (609.6m) in height that have a minimum drop of 30m and any English hill at or above 2000ft (609.6m) in height with 20m or more and below 30m of drop.

The Hewitts and Marilyns of England by Alan Dawson

The details for the hill reclassification appear below:

The name of the hill is Calf Top, and it is situated in the Central Pennines of northern England, and is positioned with the A683 and the M6 roads to its west, and has the small town of Sedbergh towards the north and the small community of Barbon towards the south-west.

Calf Top (SD 664 856) from Castle Knott

Prior to this hill’s reclassification to Hewitt status it was listed as a SubHewitt with 312m of drop based on the 609m summit spot height that appeared on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps of the day and a col height of 297m.

As its 609m summit spot height was near the benchmark height of 2000ft (609.6m) it was prioritised for a GNSS survey and this took place on the 15th April 2010.  The hill was surveyed by John Barnard, Graham Jackson and Myrddyn Phillips using a Leica 530 and two hours of data were gathered, resulting in a summit height at that time of 609.61m.

Gathering data with the Leica 530 during the first summit survey of Calf Top

As this result was so close to the benchmark height of 2000ft (609.6m) it was decided to re-visit and gather a further four hours of data.  The second survey was conducted on the 20th May 2010 by John Barnard, Graham Jackson and Myrddyn Phillips using a Leica 530, resulting in a summit height at that time of 609.62m.  As the results from these surveys were so close to the 2000ft / 609.6m height the two data sets were sent to Ordnance Survey and were processed using their Bernese software, resulting in a summit height of 609.58m.

Gathering data with the Leica 530 during the second summit survey of Calf Top

This height was reassessed in August 2016 when Ordnance Survey adopted their new OSTN15 / OSGM15 model which replaced their OSTN02 / OSGM02 model.  The adoption of the OSTN15 / OSGM15 model increased the known height of hills in England by an average of 2cm - 4cm, and in the case of Calf Top this resulted in its known accurate height increasing to 609.61m, which is higher than the minimum 2000ft (609.6) height required for Hewitt status.

The reclassification of this hill from Sub-Hewitt to Hewitt status was accepted by the list author and its new classification augmented in to the listing of the Hewitts in August September 2016.



The full details for the hill are:

Name:  Calf Top

OS 1:50,000 map:  98

OS 1:25,000 map:  2

Summit Height:  609.61m (converted to OSGM15)

Summit Grid Reference:  SD 66450 85624

Col Height:  297m

Col Grid Reference:  SD 682 867

Drop:  313m


Myrddyn Phillips (June 2019)







Mapping Mountains - Hill Reclassifications - Hewitts

Gau Graig (SH 743 140) – Hewitt reclassified to SubHewitt (3rd reclassification)


This is one in a series of retrospective Hill Reclassification posts that detail hills whose status has altered in the listing of the Welsh Hewitts (an acronym for Hill in England, Wales or Ireland over Two Thousand feet high).  These reclassification posts will give details of hills where I have direct association with their change of status, and they will tie in with a forthcoming Change Register giving detail to this list and its alterations since first publication.

The listing of Welsh Hewitts was published in booklet format by TACit Tables in February 1997 and entitled The Hewitts and Marilyns of Wales.  This list evolved out of The Absolute Summits of England and Wales which were known as the Sweats (an acronym for Summits in Wales and England Above Two-thousand FEET) and which was published by Cicerone Press in 1992 in the book entitled The Relative Hills of Britain.  The list compiler for the Hewitts and the preceding Sweats is Alan Dawson.

When the Welsh Hewitts list was published in booklet format there were 137 qualifying hills listed with their criteria being any Welsh hill at or above 2000ft (609.6m) in height with 30m minimum drop, accompanying the main list are two sub category’s entitled SubHewitts, with the two sets of criteria being any Welsh hill at or above 600m and below 2000ft (609.6m) in height that have a minimum drop of 30m and any Welsh hill at or above 2000ft (609.6m) in height with 20m or more and below 30m of drop.

The Hewitts and Marilyns of Wales by Alan Dawson

The details for the hill reclassification appear below:

The name of the hill is Gau Graig, and it is adjoined to the Cadair Idris group of hills, and it is positioned with the A487 road to its south-east, and has the town of Dolgellau towards its north north-west.

Gau Graig (SH 743 140)

Prior to this hill’s reclassification to SubHewitt status it was listed as a Hewitt with an estimated c 30m of drop based on the 683m summit spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and an estimated bwlch height of c 653m.

Gathering data with the Trimble GeoXH 6000 at the summit of Gau Graig

As the estimated drop value of c 30m is the minimum required for Hewitt status it was prioritised for a GNSS and line survey and this took place on the 1st May 2015.  The hill was surveyed by John Barnard and Myrddyn Phillips using a level and staff for determining the drop of the hill and a Trimble GeoXH 6000 to determine the summit and bwlch height and also its drop value.  The survey resulted in a 683.8m summit height and a 658.4m bwlch height, with these values giving this hill 25.4m of drop, with the line survey resulting in a drop value of 25.47m.

Gathering data with the Trimble GeoXH 6000 at the critical bwlch of Gau Graig

Determining the bwlch position for Gau Graig

The reclassification of this hill from Hewitt to SubHewitt status was accepted by the list author and its new classification augmented in to the listing of the Hewitts in May 2015.


The full details for the hill are:

Name:  Gau Graig

OS 1:50,000 map:  124

OS 1:25,000 map:  23

Summit Height:  683.7m (683.8m converted to OSGM15)

Summit Grid Reference:  SH 74377 14027 (as listed in the Hewitts)

Bwlch Height:  658.3m (658.4m converted to OSGM15)

Bwlch Grid Reference:  SH 7391 1377 (as listed in the Hewitts)

Drop:  25.4m (as listed in the Hewitts with the line survey giving 25.47m drop)


Myrddyn Phillips (June 2019)






Mapping Mountains - Hill Reclassifications - Hewitts

Thack Moor (NY 611 462) – SubHewitt reclassified to Hewitt (2nd reclassification)


This is one in a series of retrospective Hill Reclassification posts that detail hills whose status has altered in the listing of the English Hewitts (an acronym for Hill in England, Wales or Ireland over Two Thousand feet high).  These reclassification posts will give details of hills where I have had direct association with their change of status, and they will tie in with a forthcoming Change Register giving detail to this list and its alterations since first publication.

The listing of English Hewitts was published in booklet format by TACit Tables in June 1997 and entitled The Hewitts and Marilyns of England.  This list evolved out of The Absolute Summits of England and Wales which were known as the Sweats (an acronym for Summits in Wales and England Above Two-thousand FEET) and which was published by Cicerone Press in 1992 in the book entitled The Relative Hills of Britain.  The list compiler for the Hewitts and the preceding Sweats is Alan Dawson.

When the English Hewitts list was published in booklet format there were 178 qualifying hills listed with their criteria being any English hill at or above 2000ft (609.6m) in height with 30m minimum drop, accompanying the main list are two sub category’s entitled SubHewitts, with the two sets of criteria being any English hill at or above 600m and below 2000ft (609.6m) in height that have a minimum drop of 30m and any English hill at or above 2000ft (609.6m) in height with 20m or more and below 30m of drop.

The Hewtts and Marilyns of England by Alan Dawson

The details for the hill reclassification appear below:

The name of the hill is Thack Moor (having previously been listed as Renwick Fell), and it is situated in the extended Cross Fell group of hills in the northern Pennines, and is positioned with the A686 road to its south-east and the A689 road to its north-east, and has the small town of Alston towards the east and the small community of Renwick towards the south south-west.

Thack Moor (NY 611 462)

Prior to this hill’s reclassification to Hewitt status it was listed as a SubHewitt with an estimated c 57m of drop based on the 609m summit spot height that appeared on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps of the day and an estimated col height of c 552m.  

As its 609m summit spot height was near the benchmark height of 2000ft (609.6m) it was prioritised for a GNSS survey and this took place on the 22nd August 2012.  The hill was surveyed by John Barnard, Graham Jackson and Myrddyn Phillips using a Leica 530 and two hours of data were gathered, resulting in a summit height at that time of 609.645m.

Gathering data with the Leica 530 during the first summit survey of Thack Moor

As this result was so close to the benchmark height of 2000ft (609.6m) it was decided to re-visit and gather a further four hours of data.  The second survey was conducted on the 3rd March 2013 by John Barnard, Graham Jackson and Myrddyn Phillips using a Leica GS15, with Bob Smith editor of Grough joining us to write a feature on the survey, and by Aled Williams who also joined us on the summit.  The survey result at that time came to 609.625m which when converted using OSGM15 resulted in a summit height of 609.65m, which is higher than the minimum 2000ft (609.6m) height required for Hewitt status.

Gathering data with the Leica GS15 during the second summit survey of Thack Moor

The reclassification of this hill from Sub-Hewitt to Hewitt status was accepted by the list author and its new classification augmented in to the listing of the Hewitts in April 2013.


The full details for the hill are:

Name:  Thack Moor

OS 1:50,000 map:  86

OS 1:25,000 map:  31

Summit Height:  609.65m (converted to OSGM15)

Summit Grid Reference:  NY 61166 46278

Col Height:  552m

Col Grid Reference:  NY 636 456

Drop:  58m


Myrddyn Phillips (June 2019)






Mapping Mountains - Hill Reclassifications - Hewitts

Mynydd Graig Goch (SH 497 485) – SubHewitt reclassified to Hewitt (1st reclassification)


This is one in a series of retrospective Hill Reclassification posts that detail hills whose status has altered in the listing of the Welsh Hewitts (an acronym for Hill in England, Wales or Ireland over Two Thousand feet high).  These reclassification posts will give details of hills where I have had direct association with their change of status, and they will tie in with a forthcoming Change Register giving detail to this list and its alterations since first publication.

The listing of Welsh Hewitts was published in booklet format by TACit Tables in February 1997 and entitled The Hewitts and Marilyns of Wales.  This list evolved out of The Absolute Summits of England and Wales which were known as the Sweats (an acronym for Summits in Wales and England Above Two-thousand FEET) and which was published by Cicerone Press in 1992 in the book entitled The Relative Hills of Britain.  The list compiler for the Hewitts and the preceding Sweats is Alan Dawson.

When the Welsh Hewitts list was published in booklet format there were 137 qualifying hills listed with their criteria being any Welsh hill at or above 2000ft (609.6m) in height with 30m minimum drop, accompanying the main list are two sub category’s entitled SubHewitts, with the two sets of criteria being any Welsh hill at or above 600m and below 2000ft (609.6m) in height that have a minimum drop of 30m and any Welsh hill at or above 2000ft (609.6m) in height with 20m or more and below 30m of drop.

The Hewitts and Marilyns of Wales by Alan Dawson

The details for the hill reclassification appear below:

The name of the hill is Mynydd Graig Goch, and it is adjoined to the western end of Crib Nantlle (Natlle Ridge) which forms a part of the Moel Hebog group of hills, and it is positioned with the A487 road to its west and the A4085 road and the village of Beddgelert towards its east, and has the towns of Porthmadog towards its south-east and Caernarfon towards its north.

Mynydd Graig Goch (SH 497 485)

Prior to this hill’s reclassification to Hewitt status it was listed as a SubHewitt with an estimated c 71m of drop based on the 609m summit spot height that appeared on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps of the day and an estimated bwlch height of c 538m. 

As its 609m summit spot height was near the benchmark height of 2000ft (609.6m) it was prioritised for a GNSS survey by John Barnard who approached Leica Geosystems suggesting that a joint survey with the fledgling team of G&J Surveys could take place.  Leica Geosystems were enthusiastic for this to happen and the hill was surveyed on the 11th August 2008.

Mynydd Graig Goch was surveyed by James Whitworth of Leica Geosystems using a Leica SmartRover 1200 and two hours of data were gathered in conditions which can be described as being wet, resulting in a summit height at that time of 609.72m.  These data were reprocessed by Ordnance Survey resulting in a summit height of 609.75m which when converted using OSGM15 results in a summit height of 609.8m, which is higher than the minimum 2000ft  (609.6m) height required for Hewitt status.

The Leica SmartRover 1200 set-up position at the summit of Mynydd Graig Goch

The reclassification of this hill from Sub-Hewitt to Hewitt status was accepted by the list author and its new classification augmented in to the listing of the Hewitts in August 2008 and its newly acquired summit height and its ramifications was announced via a press conference on the 19th September 2008.


The full details for the hill are:

Name:  Mynydd Graig Goch

OS 1:50,000 map:  115, 123

OS 1:25,000 map:  17, 254

Summit Height:  609.8m (converted to OSGM15)

Summit Grid Reference:  SH 49732 48518

Bwlch Height:  539m (as listed in the Hewitts)

Bwlch Grid Reference:  SH 50929 48808 (as listed in the Hewitts)

Drop:  71m (as listed in the Hewitts)


Myrddyn Phillips (June 2019)







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