There is a section in Stewart's book (pp. 92-95) which gives some background to Andrew's 'enthusiasm'. Clearly the men of Islandmagee had something of a 'reputation' - "the savage disposition of these people being particularly dreaded" (Massereene/Foster MSS in PRONI - D562/3038). 'Sixty or so pikemen...(seen) on the hills of Islandmagee were only a portion of the insurgent force which had mobilised there...' A Prof Atkinson has calculated that 180 Islandmagee men.. took part in the Rising (Atkinson, Between Two Revolutions, pp. 2, 180 note 20, in Stewart p.269 note 42).
The United Irishmen was an organisation which brought together Catholics and Presbyterians and Stewart says 'there was.. no doubt about the solidly Scottish and Presbyterian character of Islandmagee by 1798. Probably no reason beyond the homogeneity of the Islanders need to adduced to explain their response to the 'turn out' (of the United Irishmen gathering for the Battle of Antrim).... Early on the Thursday morning (of 7 June) a large body of men assembled at the Knowhead Brae, under the command of William McClelland... whose family had fifty-eight acres at Portmuck.... With contingents from other parts of Islandmagee they were to muster before Redfall. The two columns from Islandmagee converged at the causeway near Ballykeel point and went on to join up with the United men from Ballycarry.' It was of course in Portmuck that a McIlhagga family farmed.
We do not know what happened to Andrew and it is unlikely that he is to be identified with a rebel who appeared in Ballymena, after the Battle of Antrim, but it may be worth recording that, according to Stewart, along with a Volunteer captain called James Brown, 'a group of insurgents from Broughshane was heard calling for sledge-hammers to smash open the lower gates of the market house. "Get tar barrels", he cried, "try it with fire". One McIlhatton got a tar barrel from the premises of a dealer in Mill Street'. McIlhatton is of course a different Scottish name from McIlhagga, though the fact that there was a McIlhagga family settled just outside Broughshane, at Ballycloghan, and that I do not know of a McIlhatton there, raises the possibility of a confusion of names in a time of great confusion in County Antrim.