Corrigan, Mairead moi´rə kôr´ĭgən [key], 1944–, Irish social activist, b. Belfast. A volunteer social worker in the Catholic neighborhoods of Belfast, Corrigan saw three of her sisters children killed when a car driven by an Irish Republican Army (IRA) terrorist went out of control after being fired on by British troops. Betty Williams , who also witnessed the incident, joined with Corrigan to form the Peace People Organization, a movement of Catholics and Protestants dedicated to ending sectarian fighting in Northern Ireland. For their work the two women were awarded the 1976 Nobel Peace Prize.