What survives is a cropmark, the ghostly outline of a rath pressed into the soil and legible only from the air, where differences in crop growth betray the buried ditches beneath. The circular enclosure, roughly 30 to 35 metres in diameter, shows up on aerial photographs as a single fosse, a term for a rock-cut or earth-cut ditch, running around the site with a width of approximately 3 to 5 metres. Two breaks in the circuit, at the east and north-west, likely indicate the positions of original entrances.

A rath is a type of ringfort, the most common form of early medieval farmstead in Ireland, typically dating from roughly the fifth to the twelfth centuries. They were enclosed homesteads, the fosse and any accompanying bank providing a degree of security for a farming household and their livestock. What makes the Knockhowlin site slightly more complex is a second, attached enclosure to the south-west. This feature appears to be contemporary with the rath itself, its defining fosse connecting directly to that of the main enclosure, suggesting both were laid out as part of a single plan rather than added at different periods. Such attached enclosures are sometimes interpreted as stock pens or ancillary yards, though the archaeological record here is too limited to say anything more precise. The low-lying, gently undulating landscape around the site would have suited mixed farming, and the presence of two linked enclosures hints at a household with some organisational complexity, however ordinary it may have been by the standards of its time.