The outlines of small paddocks arranged within a curvilinear enclosure show up as cropmarks on satellite imagery, the kind of subtle discolouration in growing crops that betrays buried ditches, or fosses, beneath the soil. The enclosure itself is modest in scale, measuring around half a metre in depth and up to thirty metres wide at its broadest, but the pattern it describes is recognisably old, a landscape of human activity that has outlasted every surface trace of the people who made it.

The site was identified and reported by Jean-Charles Caillère, whose reading of satellite imagery brought these otherwise unremarkable fields into focus as something considerably older. What he found fits into a broader cluster of activity in the immediate area. Roughly 170 metres to the north-east lies a moated site, a category of monument associated in Ireland with medieval settlement, typically a raised platform surrounded by a water-filled ditch that once enclosed a manor house or farmstead. About fifty metres to the north-east, a second and larger field system is also visible as a cropmark, suggesting that the landscape around Jamestown was once considerably more intensively organised than its present appearance would suggest. Whether these features are contemporary with one another is not established, but their proximity hints at a locality that saw sustained and layered use over time.