The fort is a subcircular rath, a type of enclosed farmstead typical of early medieval Ireland, defined by a bank and measuring roughly 39 metres east to west and 33 metres north to south. Traces of an external fosse, the drainage ditch that once ran around the outside of such enclosures, survive along the northwest to north arc, and a gap on the eastern side may be an original entrance. None of this is especially unusual in the Irish landscape, where raths number in the tens of thousands. What sets this one apart is the name it carries and the argument about what happened here.

The Battle of Aughrim was fought on 12 July 1691 and proved to be the decisive engagement of the Williamite War in Ireland. The Jacobite commander, Lieut.-General the Marquis de St Ruth, a French officer sent by Louis XIV to lead the Irish Catholic forces, was killed during the fighting, and his death contributed directly to the collapse of the Jacobite line. The fort on Aughrim Hill has long been associated with that moment. Peter Harbison, writing in 1975, identified this rath as the spot where St Ruth fell. But the military historian G. A. Hayes-McCoy, writing in 1942, located the event some 700 metres to the southeast, in an area that appears on Ordnance Survey six-inch maps under the name The Bloody Hollow, a designation that speaks plainly enough to local memory of what occurred there. The two accounts have never been fully reconciled, and the question of exactly where a cannonball killed the French general remains open.

About 230 metres to the northeast of the fort stands a named bush, a feature recorded separately as a monument in its own right. Named or fairy bushes, lone thorns associated with particular histories or beliefs, were once carefully noted and avoided in the Irish countryside, and the fact that this one merits its own record gives some sense of how layered the landscape around Aughrim remains.