In the autumn of 1867, O’Connor Power travelled to North America to discuss reorganisation with the American Brotherhood. When he returned to Ireland, he moved, in early January 1868, as the Supreme Council’s representative for Connacht, to County Mayo to set up Fenian units.*
On 13 February, his twenty-second birthday, O’Connor Power was in Dublin to meet with the Supreme Council, the governing body of the Irish Republican Brotherhood. A few days later, he was arrested on suspicion and held under the Habeas Corpus Suspension Act, a law which allowed detention without trial or evidence. He spent five and a half months in Kilmainham jail.
*SPO Fenian Files, 4 January 1868, MS 242R.