The rath at Coolyhenan, a type of ringfort built from earthen banks rather than stone, was once a legible feature in the landscape, its oval outline mapped with reasonable precision in 1924. Today, dense scrub has moved in so thoroughly that the monument is more felt than seen, its shape emerging only gradually as your eyes adjust to what the vegetation is doing.

A rath is the earthen equivalent of a stone-built cashel, typically enclosing a farmstead or the residence of a person of moderate status during the early medieval period in Ireland, roughly the fifth to twelfth centuries. The Coolyhenan example was recorded on the Ordnance Survey six-inch map of 1924 as an oval measuring approximately twenty-five metres east to west and twenty metres north to south, defined by a scarp, that is, a steep-sided earthen edge formed by cutting into or banking up the ground. By the time fieldwork was compiled by Denis Power, the monument had shrunk slightly in apparent size, measuring around twenty-three metres on its east-west axis. The surrounding fosse, a shallow external ditch that would have reinforced the enclosure's boundary, survives in a u-shaped profile roughly two and a half metres wide and just under half a metre deep. The scarp itself, just over two metres wide and a little over a metre high, has been worn down by root action and encroaching growth.

Access to the site is through private farmland, so permission from the landowner would be the first practical step. The monument sits in otherwise unremarkable flat pasture, which means there is no dramatic topography to help orient a visitor. What a careful observer will notice is the scarped edge where the ground suddenly drops away in a rough oval, and the slight depression of the fosse just beyond it. Visiting when the scrub is bare of leaves, in late autumn or winter, gives the best chance of reading the earthwork's shape. There are no interpretive signs and nothing to indicate that this is anything other than a tangled patch of ground, which is itself part of what makes finding the outline so satisfying.