Ye Ole Survey Monuments (YOSM)

The official website for the Ye Ole Survey Monuments

A series of geocaches placed nearby to trig points.

We currently have 409 Caches, 19411 Found Logs and 634 Did Not Finds in our database

The series can be added to by any geocacher by applying for a series number

What is Ye Ole Survey Monuments?

Ye Ole Survey Monuments, commonly known as YOSM (GC45CC), made its mark in geocaching history when it was placed on 25 March 2002 by outforthehunt. This traveling virtual geocache added a unique dimension to the geocaching experience, leading seekers to specific survey monuments, pillars, surface blocks, rivets, or bolts scattered across the country.

The cache, as it journeyed through various locations, allowed multiple logs since each spot was a distinctive destination. However, this practice came to an end in 2017 when Groundspeak decided to archive the cache due to changes in guidelines. Despite its archival, YOSM had already etched its place in geocaching history with an impressive tally of 25,076 finds contributed by 3,528 different cachers.


The Ye Ole Survey Monuments geocaching series is making a comeback! We strongly believe it's time to breathe new life into this series and embark on a fresh and exciting adventure.

I am delighted to share that we have the full backing and support of the original YSM Series Owner, OutForTheHunt as well as Orlando's Rat. With their blessing, we are enthusiastic about building upon the legacy of this beloved geocaching series.

The new series will focus on physical caches, akin to the cherished Church Micro, Village Signs, and SideTracked series adding an extra layer of exploration and discovery. We invite you to join us in this exciting journey to uncover the rich history of survey monuments through geocaching.

It is planned at the moment that the new series will go live on 18 April 2024, a date steeped in historical significance. On this day, a remarkable event unfolded as a group of surveyors converged around a distinctive white concrete pillar in a field located in Cold Ashby, a picturesque village nestled in Northamptonshire, England. Their mission marked the commencement of the retriangulation of Great Britain, a pivotal moment in the geographical and cartographic history of the region.

If you share my enthusiasm and wish to be a part of this revival, we are actively seeking volunteers to help place new physical caches at or near to trig-points and other survey monuments. Whether you have a favourite location or are eager to explore new areas, your involvement will contribute significantly to the success of this series.

How can I get involved?

To assist you in discovering trigpoints in your local area, we have a variety of helpful maps: 

Legacy YSM Locations: Explore all previous locations under the old YSM series by OutForTheHunt here.

UK Pillars: Discover all pillar-type trigpoints in the UK on this map here.

Alternatively, you can utilize the TrigpointingUK website at

If you prefer a more traditional approach, consult Ordnance Survey maps, where trigpoints are marked with a distinctive cyan triangle adorned with a central dot. Happy trigpoint hunting!