The earthwork at Croaghill is a subcircular rath, a type of enclosed farmstead that was the standard unit of rural settlement in early medieval Ireland, typically dating from roughly the fifth to the twelfth centuries. A rath was defined by one or more earthen banks enclosing a circular or near-circular area where a family would have lived, kept animals, and stored goods. This particular example measures approximately 62 metres east to west and 44 metres north to south, making it a reasonably substantial example of its type. It is defined by a scarp, an intervening fosse (a ditch dug to reinforce the enclosure's defensive character), and an outer bank. A possible entrance survives at the south-east, which is a common orientation for Irish raths. The interior carries an irregular hollow in its northern section, thought to be of modern rather than early medieval origin, and the outer bank has been breached on the northern side where a road passes through it.