Jones worked as a teacher and dressmaker, but after her husband and four children all died of yellow fever in 1867 and her dress shop was destroyed in the Great Chicago Fire of 1871, she began working as an organizer for the Knights of Labor and the United Mine Workers union. From 1897, at about 60 years of age, she was known as Mother Jones. In 1902, she was called "the most dangerous woman in America" for her success in organizing mine workers and their families against the mine owners. In 1903, to protest the lax enforcement of the child labor laws in the Pennsylvania mines and silk mills, she organized a children's march from Philadelphia to the home of President Theodore Roosevelt in New York.
The Mother Jones Memorial near her birthplace in Cork, Ireland
Mary G. Harris was born on the north side of the city of Cork, Ireland, the daughter of Roman Catholic tenant farmers Richard Harris and Ellen (née Cotter) Harris. Her exact date of birth is uncertain; she was baptized on 1 August 1837. Mary Harris and her family were victims of the Great Famine, as were many other Irish families. This famine drove more than a million families, including the Harrises, to emigrate to North America. Due to deaths from starvation and to the massive wave of emigration, Ireland's population fell approximately 20–25%.