McCann, John (1765–98), United Irishman, was born near Farranshane, near Antrim town, Co. Antrim; his parents’ names are unknown. Though from a catholic family, he was schooled with William Orr (qv). He migrated c.1785 to Dublin, where he was employed as a clerk with the Guinness brewery on James's St. About 1789 he was made bookkeeper to Henry Jackson (qv), substantial ironfounder, merchant, and brother-in-law of Oliver Bond (qv). Recruited to the United Irishmen in 1791, he advanced to the Co. Kildare committee and thereafter became secretary to the Leinster provincial committee. In early March 1798 he innocently disclosed to Thomas Reynolds (qv), government informer, the requisite passwords for the crucial meeting of Leinster delegates due to finalise preparations for the projected rising later that year. In consequence, McCann was one of those arrested (12 March 1798) at the house of Oliver Bond at Bridge St., Dublin by a military party under Maj. Henry Charles Sirr (qv), where the Dublin organisation of the United Irishmen was overthrown at one blow.
Among the eighty so-called ‘state prisoners’ imprisoned around the city between February and July 1798, he had the misfortune to be one of three put on trial for treason, the office of the attorney general having failed to assemble sufficient evidence to warrant trial of the remainder in custody. Like Oliver Bond and William Michael Byrne (qv), McCann was convicted of conspiracy on 17 July 1798 before judicial commission on the unassisted testimony of Reynolds, and sentenced to death. The date set for his hanging was 19 July 1798, the day before the body of state prisoners agreed with the government that executions should be halted in return for general information and their exile. Accordingly he and Byrne suffered death that morning. A sensitive and pious man, he received the sacraments on the previous night.