About Trig Bagger
Ever stood on top of a hill and spotted a squat concrete pillar with a metal plate on top? That's a trig point, and if you've ever felt the urge to touch it, photograph it, and tick it off a list, you already know why this app exists.
What is a trig point?
Trig points (short for "triangulation points") are the physical building blocks of Britain's first properly accurate maps. Back in the 1930s, the Ordnance Survey needed a way to measure the whole country precisely, long before GPS existed. Their solution was triangulation: place pillars where surveyors could see two or three others in the distance, measure the angles between them, and use trigonometry to calculate exact positions. Around 6,500 of these pillars were built across the UK, and because they needed clear sightlines, they almost always ended up on hilltops, ridges, and high open ground.
Why do people hunt them?
GPS made trig points technically redundant for surveying decades ago, but that's exactly what turned them into something else: a target. "Trig bagging" has become its own quiet obsession within hillwalking and peak-bagging circles. Every trig point marks a genuine summit with a view worth the climb, and there's something satisfying about reaching a 90-year-old slab of concrete that was placed there with real precision, real purpose, and a lot of sweat.
What Trig Bagger does
Trig Bagger turns that hobby into something you can track properly. Log the trig points you've visited, see how many you've bagged, plan routes to the ones still on your list, and watch your progress build over time, one hilltop at a time.
Whether you're chasing every trig point in a single county or just want a reason to get outside and up a hill, Trig Bagger is here to keep score so you don't have to.