Blog

What are Trig Points?

In the United Kingdom, trig points are typically concrete pillars and were erected by the Ordnance Survey. The process of placing trig points on top of prominent hills and mountains began in 1935 to assist in the accurate retriangulation of Great Britain.

Here are 10 facts we love about Trig points in the UK:

1- In the United Kingdom, trig points are typically concrete pillars and were erected by the Ordnance Survey.

2- Trig pillars are mostly made of cast concrete, but a few are built from local stone cemented together.

3- Like an iceberg, there is more of trig pillar below the surface than above it.

4- There are 6,190 trigs in the UK.

5- The highest trig pillar sits on the top of Ben Nevis, in Scotland,

6- The lowest trig pillar is at Little Ouse, sited at -1m.

7- In Scotland, there are some pillars called Vanessas, which are taller, cylindrical concrete pillars.

8- It was on April 18, 1936, that the first trig pillar was installed in a field in Cold Ashby, Northamptonshire. This was the start of the "retriangulation of Great Britain".

9- Did you know that Trig pillar locations are marked by a small blue triangle on OS maps.

10- Trig pillars have become the focus of “collectors”. This hobby is known as trig-bagging or trig-pointing, where people travel across the countryside spotting and recording as many as they can. We think Trig bagging is a pretty cool hobby!

What is Trig Bagging?

Many people enjoy "bagging" or "ticking off" a list of trigs. For example, you could hike to all the trig pillars in your country or region, or aim to reach all the trig pillars on one OS map. Did you know that Trig pillar locations are marked by a small blue triangle on OS maps.

Trig bagging is also a great activity for families, especially if you look for pillars that are located on smaller hills. Let your Little Trekkers show you the way by map and compass.

Some people set themselves the challenge of reaching a set number of trigs in a day, such as all the trigs in your local hills. You could choose to walk, run or, in some cases, cycle, to a trig!

Will you join in and 'bag' yourselves some trigs? Tag us in your adventures using #spottyotter !