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What Are Trig Points?

In the United Kingdom, trig points are those curious concrete pillars you’ll often see perched on hilltops or scattered across open landscapes. Originally erected by Ordnance Survey from 1935 onwards, their job was to help accurately retriangulate Great Britain, forming the backbone of modern map-making.

These iconic structures quickly became part of the countryside we all love to explore, and today they’re a favourite feature for walkers, hikers, and mini adventurers alike!

10 Fascinating Facts We Love About UK Trig Points

1. Trig points are typically concrete pillars set up by Ordnance Survey.

2. Some are made from local stone instead of concrete, blending beautifully into the landscape.

3. Like an iceberg, there’s often more trig pillar hidden below ground than above!

4. There are exactly 6,190 trig points across the UK.

5. The highest trig sits atop Ben Nevis, Scotland’s tallest peak.

6. The lowest is at Little Ouse, lying at -1 m below sea level.

7. In Scotland, you might spot taller, cylindrical versions called Vanessas.

8. The very first trig pillar was installed on April 18, 1936, at Cold Ashby, Northamptonshire.

9. On OS maps, trig points are marked with a small blue triangle.

10. Trig pillars have inspired thousands of “trig-baggers” – hobbyists who travel the UK to find and log as many as they can!

So… What Is Trig Bagging?

Trig bagging is the fun challenge of visiting and logging trig points — think of it like peak bagging or geocaching, but with historic pillars instead of mountain summits!

Whether you’d like to:

• Tick off all the trigs in your local area

• Complete every trig on a specific OS map

• Or set yourself a daily trig-challenge to walk, run or cycle to several at once...

There’s a trig adventure waiting for you!

Family-Friendly, Fun & Educational

Trig bagging is brilliant for families, especially if you pick trigs on smaller hills. Let your little explorers lead the way with a map and compass — it’s a fantastic way to learn navigation skills, build confidence, and spend quality time outdoors together.

And don’t forget your Spotty Otter waterproofs, fleeces, and wellies, perfect for muddy trails, sudden showers and breezy hilltops!

Will You Join the Trig-Bagging Fun?

Start spotting, climbing and collecting these historic pillars and share your adventures with us! Tag us in your photos and use #spottyotter so we can follow along.

Ready, set… bag those trigs!