PRONI has a lot of papers on the United Irishmen in and around Co. Antrim. Search the PRONI e-catalogue to find them. An example is T3541/5/2 which is the autobiography of John Caldwell jr who describes his involvement in the 1798 uprising in the Ballymoney area. He was eventually apprehended and like many of the middle ranking officers, was offered the choice of facing trial for treason (penalty for which was often hanging) or being banished from the Kingdom for life. Like most, he sensibly chose banishment and, after many delays, sailed for America. It’s a lengthy document.
For most of PRONI’s records you need to go in person and look them up but a few are on-line. An example is this (D2095/178) at PRONI which is the text of a talk, first given in the 1920s I believe, about The “Hearts of Steel” in the Larne area in the late 1700s.
https://apps.proni.gov.uk/eCatNI_IE/ResultDetails.aspxAnother is the “Black Book of the Rebellion of the North of Ireland” (D272/1) which can be downloaded free.