That seasonal isolation is, in a quiet way, the most revealing thing about it.

A rath is a ringfort, the most common type of early medieval monument in Ireland, typically a circular enclosure defined by one or more earthen banks and ditches, used as a farmstead or settlement from roughly the sixth to the twelfth century. The Ballymalis example is a modest one. When the Ordnance Survey mapped this part of Kerry in 1846, the enclosure appeared on the six-inch sheet with a diameter of around twenty-five metres. By the time the revised six-inch map was produced in 1895, the same feature was recorded at approximately thirty-five metres across. Whether that difference reflects actual change to the earthwork, shifting survey methodology, or simply the difficulty of measuring a waterlogged site accurately is not clear. What it does suggest is that the monument was already ambiguous on the ground in the nineteenth century, and remains so. The rath sits in an area described as liable to flooding, which means that for a good part of the year, the river effectively reclaims the field around it.