That is an oddly common way to discover ancient field systems: the human eye, moving at walking pace through grass and undergrowth, tends to read a low ridge as a natural undulation rather than something deliberately built. From the air, the straight lines give the game away.

The banks were first identified through aerial photography and surveyed in 1996 and 1997 as part of a wider study of the Lee Valley area. They run in several directions, suggesting either multiple phases of use or a planned field layout that extended across a considerable area. The lengths vary significantly, from around 46 metres up to approximately 230 metres, and where the larger banks survive at ground level they stand on average about 0.30 metres high and between three and four metres wide. That is modest in height, which explains why they had not been catalogued earlier; a bank of that profile, especially one that has been grazed or ploughed over centuries, can look like little more than a gentle rise in the terrain. The earthen field boundary was a widespread and practical technology across early Irish agriculture, used to define plots, manage livestock, and mark ownership or tenure, and examples survive in varying states of preservation across the country.