That alone is worth pausing over. Field boundaries are among the most common and most overlooked features in the Irish landscape, yet the oldest of them can be extraordinary survivals, in some cases predating written history by millennia. The celebrated Céide Fields on the north Mayo coast, for instance, preserve a Neolithic farming system beneath the bog that is more than five thousand years old. Whether the boundary at Troiste belongs to anything like that tradition, or represents a much later organisation of land, is a question the available record cannot yet answer.

Field boundaries as archaeological features tend to attract attention when they preserve evidence of early land division, when they are associated with other monuments nearby, or when their construction method, such as a stone-faced earthen bank or a clearance cairn wall, suggests a particular period of use. Mayo's landscape carries layers of agricultural history compressed into its surface, from prehistoric farming communities to the dramatic reorganisation of land during and after the plantation era and the clearances of the nineteenth century. A boundary in this part of the west could belong to almost any of those periods, which is part of what makes even an unassuming line of stones or earth worth noting down.