TrigpointingUK is a website providing information about Ordnance Survey trigpoints. It has a database of all known trigpoints in Great Britain, and many in Ireland, and allows users to log visits to them.
TrigpointingUK was conceived early in 2003, by Mark Thompson (TheCat) and Ian Harris (Teasel), the creators of the GeocacheUK website. The geocaching.com website had recently added a "benchmarking" feature, allowing US NGS benchmarks to be logged, but resisted calls to allow stations outside of the US to be added. A new site was envisaged to plug that gap, at least for trigpoints in the UK, and the name "Trigpointing" was chosen to complement "Geocaching" and "Benchmarking".
The site first went live on 19/04/2003. Since then over 2000 people have logged over 160,000 visits and uploaded over 130,000 photographs.