Catherine "Cate" O'Leary (née Donegan; March 1827 – July 3, 1895) was an Irish immigrant living in Chicago, Illinois, who became famous when it was alleged that an accident involving her cow had started the Great Chicago Fire of 1871. Born Catherine Donegan, she and her husband, Patrick O'Leary, had three children, one of whom, James Patrick O'Leary, ran a well-known Chicago saloon and gambling hall.
