As peat extraction removes the bog layer, a grid of pre-bog walls has emerged, their long axes running roughly northwest to southeast and northeast to southwest, forming what appears to be a system of large rectangular fields. The whole complex stretches approximately 500 metres east to west and 400 metres north to south, a considerable area that speaks to organised, deliberate land use at a time before the bog formed over it entirely.

Pre-bog field systems of this kind, sometimes called relict field systems, are the preserved remains of farming landscapes that were swallowed by blanket bog as the climate became wetter and the land less workable, a process that began in many parts of the west of Ireland during the Bronze Age and continued into the early medieval period. The walls at Ballynew vary considerably in their construction, ranging from loosely laid stone to larger boulders used to revet, or face, a rubble core, suggesting either different phases of building or variation in the resources available across the site. The pattern was documented by Gibbons and Higgins in 1988 and later included in the published Archaeological Inventory of County Galway, compiled by Paul Gosling. What makes the site quietly remarkable is scale: this is not a single buried wall glimpsed at a bog edge, but something approaching a coherent former landscape, preserved precisely because the bog that obscured it also protected it.