Mapping Mountains – Significant Height Revisions – The Fours – The 400m Hills of England

 

Kilnsey Moor (SD 948 669) 

There has been a Significant Height Revision to a hill that was provisionally listed in the The Fours – The 400m Hills of England, with the summit height, col height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Kilnsey Moor (SD 948 669)

The criteria for the list that this height revision applies to are:

The Fours – The 400m Hills of England - English hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main list is a sub list entitled the Sub-Fours, the criteria for which are all English hills at or above 400m and below 500m in height that have 15m or more and below 30m of drop.  The list is co-authored byMyrddyn Phillips and Aled Williams and is available to download in Google Doc format from the Mapping Mountains site.

The Fours - The 400m Hills of England by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Kilnsey Moor, and it is adjoined to the Pen y Ghent group of hills, which are situated in the Pennines of northern England, and it is positioned with a minor road to its south, and the B6160 road to its east, and has the village of Threshfield towards the south-east.

When the Introduction to the first group of hills for the updated and revised listing of the The Fours – The 400m Hills of England was published by Mapping Mountains on the 10^th September 2022, it was announced that the accompanying sub lists were being revised with the two 390m categories dispensed with and the criteria and name of the 400m Sub-Fours revised.  The one accompanying sub list is now named the Sub-Fours with its criteria being all English hills 400m and above and below 500m in height that have 15m and more and below 30m of drop.

Prior to this revision this hill was listed with 15m of drop, based on the 468m summit spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map and the 453m col spot height that appears on the Ordnance Survey 1:25,000 Explorer map. 

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

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

LIDAR summit image of Kilnsey Moor (SD 948 669)

LIDAR analysis gives the height of this hill as 463.4m, and when compared to its originally listed summit height this comes within the parameters of the Significant Height Revisions used within this page heading, these parameters are:

The term Significant Height Revisions applies to any listed hill whose interpolated height and Ordnance Survey, Harvey or other interactive map summit spot height has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or analysis of data produced via LIDAR.  Also included are hills whose summit map data is missing an uppermost ring contour when compared with the data produced by the Trimble or by LIDAR analysis.

Therefore, the new listed summit height of this hill is 463.4m and this was derived from LIDAR analysis, this is 4.6m lower than the originally listed summit height, which was based on 468m spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map. 

 

The full details for the hill are:

Group:  Pen y Ghent

Name:  Kilnsey Moor

OS 1:50,000 map:  98

Summit Height (New Heigt):  463.4m (LIDAR)

Summit Grid Reference:  SD 94838 66954 (LIDAR)

Col Height:  453.4m (LIDAR)

Col Grid Reference:  SD 94926 67281 (LIDAR)

Drop:  9.9m (LIDAR)

 

Myrddyn Phillips and Aled Williams (October 2025)