Mapping Mountains – Hill Reclassifications – Y Trichant – The 300m Hills of Wales

Gyrn (SJ 165 585) – Sub-Trichant addition

There has been an addition to the list of Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail on contemporary maps produced from Ordnance Survey data.

The criteria for the list that this addition applies to are:

Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13th May 2017.

Y Trichant - The 300m Hills of Wales by Myrddyn Phillips

The name the hill is listed by is Gyrn, and it is adjoined to the Bryniau Clwyd group of hills which are situated in the north-eastern part of North Wales (Region A, Sub-Region A2), and it is positioned with the A494 road to its west, south and east, and has the town of Rhuthun (Ruthin) towards the west.

When the original 300m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website this hill was not included in the Hills to be surveyed sub list that accompanied the main P30 list, as it was considered not to meet the criteria then used for this sub category. 

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with 26m of drop, based on the 384m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and the 358m bwlch spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map.

Extract from the Ordnance Survey 1:25,000 Explorer map

Therefore, the addition of this hill to Sub-Trichant status is due to detail on contemporary maps produced from Ordnance Survey data, resulting in a 384m summit height and a 358m bwlch height, with these values giving this hill 26m of drop, which is sufficient for it to be classified as a Sub-Trichant.

The full details for the hill are:

Group:  Bryniau Clwyd

Name:  Gyrn

OS 1:50,000 map:  116

Summit Height:  384m (spot height)

Summit Grid Reference:  SJ 16519 58531 (spot height)

Bwlch Height:  358m (spot height)

Bwlch Grid Reference:  SJ 16719 58839 (spot height)

Drop:  26m (spot height summit and bwlch)

Myrddyn Phillips (September 2020)