For some people, exploring the craggy hills and valleys of Greater Manchester and the surrounding areas is the perfect way to spend a weekend. The region is cradled by rugged, high-altitude moorlands and rural hills.
People living here are rarely more than 30 minutes away from some of the most dramatic and wild landscapes in Britain. From the moody, gritstone plateaus and peat bogs of the Dark Peaks, to the rugged valleys of the Southern Pennines, there are plenty of places to embrace looking windswept and interesting.
But for those familiar with many walks and trails on offer, it’s likely they will have spotted some mysterious landmarks along the way. One would be the strange, unnatural obelisks jutting out on high ground like little druidic lighthouses.
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For those unfamiliar with the sight, they might wonder what exactly their purpose is. These artefacts are known as trig points, or triangulation pillars, and once had a crucial role in how we saw Britain.
In the days before GPS and satellite mapping, trig points revolutionised map-making in the country. The first trig point was placed in a field in Cold Ashby, Northamptonshire, on April 18, 1936.
It was the start of a colossal project led by Brigadier Martin Hotine for the Ordnance Survey (OS) to remap the country.
The Trig Point at the summit of Crompton Moor, in Shaw and Crompton, Greater Manchester, England. January 29, 2009(Image: By Jza84 – Own work, CC BY-SA 3.0)
Before this, British maps were based on a patchwork of observations that no longer supported the accurate mapping needed for a rapidly developing 20th-century nation.
The iconic pillars were placed to provide a stable, level base for survey equipment. By the time the project ended in 1962, more than 6,500 pillars had been erected across the country. While many are made of concrete, others are constructed from local stone.
How trig points work
Imagine you are trying to draw a giant map of the whole country. To make sure everything is in the right place, you need anchor points.
Trig points are like giant ‘X marks the spot’ stickers on hills and high ground. By standing at one pillar and looking at two others nearby, you can imagine drawing a massive triangle in the sky.
Tandle Hill trig point, Oldham. October 18, 2014(Image: Photo © John Slater (cc-by-sa/2.0))
By connecting pillars across the land, you create a giant jigsaw puzzle of triangles. This tells map-makers exactly where every hill and valley belongs.
In the 1990s, the emergence of GPS and satellite technology rendered the traditional trig point obsolete for professional surveying.
However, despite being scientifically obsolete, they have since become iconic features of the British landscape, with most still standing in the UK today.
Trig Pont near Watergrove Reservoir in Wardle, Rochdale. July 22, 2022(Image: Photo © thejackrustles (cc-by-sa/2.0))
They are also still marked on OS maps with a small blue triangle, serving as a reliable backup for hikers when digital signals fail.
They have even spawned the popular hobby of ‘trig-bagging’, where hikers attempt to visit as many pillars as possible.
To mark the 90th anniversary of the retriangulation, the C20 Society (Twentieth Century Society) has applied to Historic England to list the first and last pillars ever placed: the 1936 pillar at Cold Ashby and the 1962 pillar at Thorny Gale, Cumbria, as Grade II-listed.
The trig point on Broadstone Hill in Diggle, Oldham, 2007(Image: By Bill Boaden, CC BY-SA 2.0)
Catherine Croft, Director of the C20 Society, is quoted on the organisation’s website as saying: “Long before GPS, satellite technology, and navigational apps on our mobile phones, Trig Points were the humble concrete pillars that mapped a nation – more than 6,500 of them in total.
“As the landmark ‘Retriangulation of Great Britain’ celebrates its 90th anniversary, we spied an opportunity to put a figurative pin-in-the-map and have submitted the two most historically important Trig Points – the first and last examples – to be nationally listed.
Brown Edge Trig Point, Oldham. July 19, 2022(Image: thejackrustles, CC BY-SA 2.0)
“Nothing beats the modest triumph of standing on top of a Trig Point in a brisk wind and we hope these two modern obelisks of concrete in the countryside will soon be recognised by DCMS (The Department for Culture Media and Sport).”
There are many points across the Greater Manchester region where trig points can be found if you fancy yourself as a bit of a ‘trig-bagger’.
A handy map of the trig points can be found on the TrigpointingUK website here.