Triangulation Pillar GPS Waypoints

Trigpoint Bagging...

This site can be used by Members for recording your trig bagging exploits, as well as suppliying you with the GPS waypoints of all the trigpoints.

  • Once you are registered as a member this link will allow you to 'bag' those trigpoints on the major hills of britain.
  • Whereas the "by OS Area: HP to TV" links on the left sidebar here, allow you to bag all trigpoints in each of the Ordnance Survey Grid Reference areas.

310 UK Primary Triangulation Points

The UK network of concrete pillar triangulation points was built and measured between 1936 and 1962 by the Ordnance Survey, for a project known as the Retriangulation of Great Britain. This smaller file lists the pillars and some roof bolts in the primary network, whose measurement led to the seamless mapping we enjoy today. The original trigpoint numbers, names and OSGB coordinates are given.

All 6557 UK Triangulation pillars in OSGB Download...

These files lists all the UK trigpoint pillars (including primary ones) in the original OSGB form. The heights given relate to Ordnance Datum Newlyn (ODN), the waypoint identities are John's own with a 6 prefix (not compatible with the primary file). The GPSU file is most suitable for non-gps use.

(All GPS Formats - OSGB format and datum)

UK Trig. Points in WGS84 Datum

This GPSU text file lists the same UK trigpoints but the coordinates have been converted to WGS84 datum using the on-line converter on the Ordnance Survey GPS website. Heights are still ODN, and the waypoint identities have a 5 prefix, (not compatible with the primary file). The horizontal coordinates in this file are most suitable for use with a GPS navigator.

(GPSU .txt format only - WGS84 Datum)

For all files, please note:

  • The above two text files are GPSU compatible - and GPX, KML & AEF versions are also available. ;
  • The data was provided by the Ordnance Survey who have kindly their given permission to post on the web.
  • Thanks are due to Jonathan de Ferranti and Phil Newby for their help in producing these files.
  • The coordinates have been rounded to the nearest metre, and are not guaranteed to be accurate.
  • Where height data was not available, 8888 appears in the height column.
  • WGS84 ellipsoid heights can be obtained by converting the OSGB file to WGS84 using GPSU. Garmin say the GPS12 always reads WGS84 ellipsoid height
  • Some of the pillars may have been moved, removed or you may need the landowners permission to visit them.
  • Some of the pillars are still in use as Passive GPS Stations, maintained by the Ordnance Survey. Further data may therefore be obtained by visiting their web site at You will have to register, free of charge, to use the Passive Station database and on-line converter.
  • Further information on trig pillars can be found at and at
  • An excellent explanation of UK coordinate systems can be found in "A guide to coordinate systems in Great Britain" which can be downloaded from here.

Trigpoint Files contributed by John Davis       johndavis @ waitrose . com