That a single lake should contain such a cluster is quietly remarkable. The largest sits roughly 230 metres from the shore, towards the north-east, and it is this one that carries the most unsettling detail in its excavation record: an iron cannon ball, sitting among the more expected domestic debris of pots and metalworking tools.

Barron excavated that north-eastern crannóg across two seasons, in 1937 and 1938, and found evidence of two distinct periods of use. The earlier occupation has not been precisely dated, but the second was placed in the sixteenth or seventeenth century. By that point the structure measured roughly 10.6 metres by 9 metres, an irregularly shaped platform of horizontal beams and twigs, with what may have been the remnants of a stockade around its edge. The finds were notably varied: six pots, five crucibles, two fragments of a mould, and the cannon ball. The crucibles and mould pieces suggest metalworking was taking place on or near the island, while the cannon ball points in a different direction entirely. Local tradition holds that Knockbride old church, which stands on the shoreline of the same lake, was attacked by Cromwellian troops, and it is possible that the cannon ball arrived at the crannóg during the same episode of violence. Whether it was fired at the island or simply ended up there in the aftermath is not recorded. A stone trough, now kept at a house on the shoreline, is thought to have originated on one of the other crannógs in the lake, a small domestic object that has simply migrated from water to land over the intervening centuries.