Ringforts, known in Irish as raths, were the most common form of rural settlement in early medieval Ireland, typically consisting of a circular area enclosed by one or more banks and ditches. They served as farmsteads and homesteads for farming families of varying status, and tens of thousands of them survive across the island in various states of preservation, each one a faint outline of a life once lived inside it.

The example at Tonroe is recorded as a rath, the term generally applied to earthen ringforts as distinct from those built with stone walls, which are called cashels or cahers. Mayo has a considerable concentration of such monuments, reflecting the dense settlement of the early medieval period across the west of Ireland, roughly from the fifth to the twelfth centuries. Beyond its classification and location, the specific details of this particular fort, its dimensions, its condition, the number of its enclosing banks, and any finds or features associated with it, are not currently available from the public record.