BenchmarksGB

BenchmarksGB: Discover, Identify & Log Britain’s Ordnance Survey Benchmarks.

Whether you’re a keen walker, a history lover, or simply enjoy exploring Britain’s hidden details, BenchmarksGB turns every outing into a mini treasure hunt.

BenchmarksGB is the easiest way to spot, learn about, and record the historic Ordnance Survey benchmarks scattered across Great Britain. These engraved marks - used to measure height above sea level before modern surveying - can still be found on older buildings, bridges, churches, and walls all around the country. There are over 500,000 of them listed in the Ordnance Survey archive.

Using data from this archive, BenchmarksGB displays benchmark locations on an interactive map, helping you find them while out walking, exploring, or travelling.

With the app you can:

• See benchmark locations using detailed OS archive data

• Record your visits and mark whether each benchmark is still present

• Track your progress as you spot more across the country

• Add an extra layer of fun to your walks and holidays