A rath, sometimes called a ringfort, is one of the most common monument types in the Irish landscape, typically a roughly circular enclosure defined by earthen banks and ditches. What sets this particular example in Rosetown apart is the way its builders chose to use the land itself as a defensive partner. Rather than constructing a self-contained enclosure on open ground, they positioned the site right at the eastern edge of a very steep drop to the River Liffey, then scarped and reshaped the riverbank to create the monument's western side. The result is an oval enclosure measuring roughly 54 metres north to south and 42 metres east to west, with an inner and outer earthen bank separated by a fosse, that is, a ditch, which reaches a depth of nine metres below the inner bank at its western point. The ground inside slopes gently downward from east to west, following the natural fall of the terrain toward the river below.

The fosse curves around from the south-southeast, sweeping westward and then northward, with the Liffey running roughly 70 metres further west of the site. This arrangement meant that anyone approaching from the river valley faced both the steep natural drop and the engineered earthworks above it, while the constructed defences concentrated effort where the natural topography gave least protection. The monument has not survived entirely intact. A modern field boundary cuts across the eastern side, running north to south, and this truncation means the original enclosing elements are no longer visible when approaching from the north, east, or southeast. The site is now heavily overgrown with trees and sits within pasture, which gives it a quietly obscured quality that the western and southern sections, where the deep fosse remains most pronounced, do not fully prepare a visitor to expect from the damaged eastern face.