At around five in the morning on 24 May 1798, roughly three hundred United Irishmen were gathered inside an old churchyard on a hill south of Kilcullen, watching the countryside below. They had spent the night mobilising after a series of failed attacks on nearby towns, and the elevated position gave them a clear view of anyone approaching across the fair green. What they were watching for came soon enough: a Crown force of approximately two hundred soldiers, cavalry and infantry together, advancing from the direction of Castlemartin House, about two miles away. The old stone wall enclosing the churchyard, which still stands to around 1.2 metres, would have marked the boundary of that first, violent encounter. It is an odd kind of landmark, a place that looks like a quiet rural ruin but was, for a few hours, the opening scene of one of the earliest major engagements of the 1798 rebellion in the east midlands.

The man sent to suppress the insurgents was Lieutenant General Sir Ralph Dundas, whose headquarters at Castlemartin gave him little time to organise once word reached him of the assembly at Old Kilcullen. His force comprised around 120 infantry of the Suffolk Fencibles, commanded by Captain Beale, and approximately 80 cavalry drawn from the Romney Fencibles under Captain Cooke and the 9th Dragoons under Captain Erskine. The cavalry moved faster than the infantry and arrived at the churchyard first, a tactical problem that shaped how the engagement unfolded. Crown forces were ultimately defeated at Old Kilcullen and fell back northward to Kilcullen Bridge, where a second engagement took place around Turnpike Hill, a prominent rise about a kilometre north of the town. That hill, now largely in private ownership as part of Castlemartin Stud, carries an older mark of significance too: a tumulus, a prehistoric burial mound, sits at its summit, suggesting the hill's commanding position was recognised long before 1798. Dundas had earlier launched his failed attacks in Kildare after nights of rebellion across Ballymore-Eustace, Naas, and Prosperous had all come to nothing for the insurgents.

The battlefield landscape is unusually legible for a site of this age. Comparisons between contemporary accounts of the fighting and the First Edition Ordnance Survey map, surveyed in 1837 and 1838, suggest the terrain had changed little in the forty years after the battle. The churchyard at Old Kilcullen, which contains the ruins of a church, a round tower, a cross, and a graveyard, remains accessible and retains its enclosing stone wall. The road once considered the main route between Old Kilcullen and Kilcullen Bridge is still in use. From the churchyard, the hill fort of Dun Ailline is visible to the northeast, a reminder that this elevated ground has drawn people to it, for defence or assembly or ceremony, across many centuries.