The Mapping Monuments Bi-Centenary OS Survey Celebration was a community heritage project funded by The National Lottery Heritage Fund. It was delivered through a collaboration between Queen’s University Belfast (QUB), Causeway Coast and Glens Heritage Trust (CCGHT), and a dedicated volunteer team of more than 20 local participants.
The project was centred on the historic landscape of the Magilligan and Binevenagh area, which played an important role in the first Ordnance Survey of Ireland. Completed in 1847, this survey was the first attempt to map an entire country at large scale. The flat geomorphology of the area was the location of an eight-mile baseline which ensured the accuracy of the survey. Although invisible today, the Baseline’s position is marked by three precisely aligned circular structures known as basetowers, located at Ballykelly, Minearny and Ballymullholland. Alongside the basetowers, the wider landscape preserves other traces of historic survey activity, including 19th- and early-20th-century benchmarks chiselled into bridges, walls and buildings.
Volunteers participated in a series of online and in-person workshops, as well as fieldwork and local research, to locate traces of the Ordnance Survey in the Lough Foyle landscape. This included creating an inventory of local benchmarks, undertaking archival research, and conducting the first geophysical survey of one of the surveyors’ encampment sites at Bellarena Estate. The results of this research have been added to the project website.
The volunteers also undertook training in source reliability, copyright, accessibility and interpretative writing, enabling them to co-create content for a large touring exhibition. The exhibition launched at the project’s celebration conference in November 2023 in Ballykelly, where broadcaster Joe Mahon opened the event by reflecting on the legacy of Ordnance Survey scholar John O’Donovan. Speakers included a mix of volunteers who had been working directly on the project, alongside academics and artists who explored both the project’s findings and the wider legacy of the Ordnance Survey in Ireland.
The touring exhibition has since been displayed at Tollymore National Outdoor Centre, Roe Valley Cultural Arts Centre, Armagh County Museum, the Tower Museum in Derry, PRONI, and a selection of public libraries throughout Northern Ireland. The research has also been distilled into a publicly available booklet, Mapping Monuments: The Lough Foyle Baseline, written by project volunteer and retired surveyor Michael Cory.
Across the project, volunteers contributed more than 860 hours of time, developing new skills in archaeological survey, archival research, digital mapping, and heritage communication. The project, the conference, the booklet and the ongoing travelling exhibition all provide a lasting legacy that ensures Ordnance Survey heritage reaches a wider audience, enabling more people to recognise and value the structures and landscape traces associated with this unique aspect of local and national history. This was acknowledged at the Heritage Angel Awards 2024, when Mapping Monuments was highly commended in the Best Research or Interpretation of a Historic Building or Place category.