Ballingarry Castle, at Cloghaneleesh, began as something resembling a promontory fort, a type of defended headland where natural geography does much of the defensive work, with curtain walls and a gateway closing off the landward side. That earliest phase dates to around 1280, built by the Cantillon family, and the semi-circular bank they raised on the mainland still runs for roughly 120 metres. What makes the site unusual is not any single structure but the way later builders kept adding to it, cutting across and through what came before, so that the earthworks visible today are a palimpsest of different conflicts laid one on top of another.

The Cantillons held the castle until 1585, when their lands were granted to George Isham following what appears to have been a fairly hands-off arrangement; he took head rents and left the occupants in place. That quieter arrangement did not last. By 1602 Garrett Roe Stack, brother-in-law to Lord Kerry, had garrisoned Ballingarry, and Sir Charles Wilmot besieged it for over a year. In 1603 Gerald Mac Morris surrendered and was executed along with other leaders. The site then enters its most elaborately documented phase during the Cromwellian wars, when Colonel David Crosbie, a loyalist, took control and set about strengthening the defences considerably. He extended the fortress beyond the isthmus, dug the two long trenches that radiate out in a V-shape from his turret on the landward side, and built houses on the peninsula to accommodate English settler families. The north-west trench runs approximately 120 metres; the north-east trench runs closer to 175 metres and once terminated at a watchtower on the cliff edge, now entirely gone. A smaller trench connects the drawbridge to the northern headland, cutting across the earlier semi-circular earthwork. According to Charles Smith, writing in 1756, these trenches functioned as subterranean passages offering protected movement for Crosbie's garrison. Crosbie held out through repeated sieges between 1641 and 1645, sustained by food and ammunition supplied by Lord Inchiquin of Clare. The whole arrangement collapsed on 15 February 1645, when a Sergeant James Kelly lowered the drawbridge and let the besieging Irish forces enter. Crosbie, seriously ill, was taken to Ballybeggan Castle near Tralee to be executed, but was rescued through the efforts of his niece Katherine MacGillicuddy and his nephews, Colonels MacElligott and MacGillicuddy. He recovered his estates in 1651 and died seven years later, buried at Ardfert.

What survives at ground level today rewards patient looking. Crosbie's turret still stands on the landward side, though ruined and measuring only about 1.8 metres by 1.2 metres high. The V-shaped trenches, each consisting of paired mounds with an internal fosse (a defensive ditch), can be traced across the headland, the north-west arm descending into a deep hollow as it cuts through the earlier Cantillon earthwork. The north-east trench, which once carried a branch extending westward noted by the antiquarian Westropp in 1909, has been obscured in places by later field banks. The drawbridge is gone, but its position can be inferred from the smaller connecting trench that runs north across the headland. The layers here are genuinely readable in the landscape if you know what you are looking at.