- Main article: Mary Driscoll
Annie ClarkAnnie Clark was a friend of Mary Driscoll. She was from Maine where she was the youngest and only girl in her family. One day, her oldest brother confessed that their mother was not Annie's real mother. Annie left a week later and began working in Lowell, Massachusetts at a mill. There she lived in a boardinghouse with several girls, including Laura Austin and Ruth Shattuck. In July 1847, Annie helped train Mary at the mill. They gradually became close friends. Annie left the mill and traveled west the next year. She met her husband, Silas Marks who was a lawyer, in Racine, Wisconsin.
Kate Kelly (née Driscoll; born c. 1829) was the older sister of Mary. She was self-absorbed, her favorite subject to talk about being herself. Mary also described her sister as having "two faces". Kate was not really fond of Mary, though she pretended to be in front of others. In 1845, she left her home in Skibbereen, Ireland and settled in Lowell. She worked as a maid servant for Mrs. Abbott, the wife of a mill agent. Kate was proud to be Mrs. Abbott's favorite and bragged about it endlessly. She continued working for Mrs. Abbott until her marriage to Dennis Kelly in 1851. The couple had two children.
Laura Austin was a good friend of Annie Clark. She lived in a boardinghouse, where she shared a room with Annie, Ruth Shattuck, and Clarissa Burroughs. Laura began working at the mill sometime during 1841. She once signed a petition that got her on the "list", marking her as "willful" and a "troublemaker". Laura later became good friends with Mary, who she met through Annie. In late 1847, she decided to quit the mill and went with Mary to help Sean Riordan in Boston. She later helped Mary place Alice O'Donnell at Perkins Institute for the Blind, where she was well taken care of.
Nora KinsellaNora Kinsella was the aunt of Kate and Mary Driscoll. She was particularly fond of Mary, whom she called "Quiet One". In 1841, she left Ireland and immigrated to America. She worked as a teacher in Lowell and earned enough money for her nieces' passage to America. In July 1847, Mary came to live with Nora. The two of them then began saving money for Mary's parents to come over, until the received word about their deaths. She later gave Mary her money to help Sean. Nora continued teaching in Lowell until the 1870s.
Patrick QuinnPatrick Quinn was Sean Riordan's uncle. In 1842, he immigrated from Ireland to Boston, where he opened a tavern. He paid for his nephew's passage to America. In June 1847, Patrick helped Mary find Alice O'Donnell. After seeing her poor living conditions, he took her in for a short time and later sent her to a convent. In late 1847, Sean was caught in some trouble but Mary was able to help Patrick with the bail money. In later life, he became a wealthy and influential man in Boston's politics. The Irish community "loved and respected" him.
Sean RiordanSean Riordan was a friend of Mary whom she met on the ship to America. His uncle, Patrick Quinn sent him the money for his ticket. Upon arriving in America, he and his uncle looked after Mary and helped her locate Alice. Sean had a hard time finding work because he was Irish, writing to Mary that it may have been "a mistake to come [to America]." He later obtained a job in Somerville. After helping Alice when riot broke out, Sean was thought to be involved and was charged with accessory to murder. Mary provided his bail money and Sean disappeared.
- Mr. Abbott was the mill owner in Lowell, Massachusetts where Mary Driscoll worked.
- Mrs. Abbott was the mill owner's wife. She employed Kate Driscoll as her maid servant. Kate also claimed to be her favorite.
- Alice O'Donnell (born c. 1834) was the blind daughter of Mr. and Mrs. O'Donnell. Mary, who had known her parents, later found Alice living in poor conditions in Boston. Mr. Quinn took her in for a short time, before he sent her to live at a convent. After the convent was burned, Mary helped place her in Perkins Institute for the Blind.
- Brendan Corcoran (born c. 1838) was the son of Mr. and Mrs. Corcoran and the older brother of Molly and Sophie. He was not happy about moving to America and took a while to warm up to Mary.
- Mr. Byrnes (died August 12, 1847), a teacher who disciplined one of his students too harshly. He later fell from the roof of the church and died.
- Clarissa Burroughs (died October 1, 1847), a girl who lived at the same boardinghouse as Annie Clark and also worked at the mill. She disliked the Irish and believed them to be the problem with the mills. Clarissa was once caught secretly meeting a boy. She died when her hair was caught in her machine at the mill.
- Mr. and Mrs. Connelly were neighbors of the Driscolls in Ireland. She gave Mary some oatmeal cakes for the passage to America.
- Mr. and Mrs. Corcoran were the parents of Brendan, Molly, and Sophie. She was "fine company", while Mr. Corcoran mostly kept to himself. Once they reached America, Mr. Corcoran was held back by the medical officer, meaning he was likely sent back to Ireland.
- Mr. and Mrs. Driscoll (died 1847) were the parents of Kate and Mary. She was happy that Mary was going to America, but he was not pleased about it. Mary later received a letter, stating that they had died.
- Eunice Currier was a mill girl who lived in the same boardinghouse as Annie. She worked in the dressing room, which was less noisy and had "cleaner" air.
- Fiona Buckley, a neighbor of Nora and Mary. Some boys injured her by hitting her with rocks. She was traumatized by the incident. Her family lived in a small house.
- Mr. Fowler was the overseer at the mill in Lowell. He kept a close eye on Mary. Mr. Fowler got more money when he pushed the girls to work harder. As such, his behavior was sometimes bordering abusive.
- Mrs. Jackson was the keeper of the boardinghouse where Annie lived.
- John and Mrs. Delaney were a mother and son who boarded at Nora's house. They began staying there when Mr. Delaney left. John later got a job digging holes in a cemetery.
- Maureen was Mary's best friend in Ireland. She wanted to go to America with Mary, but her family had no money for the ticket.
- Molly and Sophie Corcoran (born c. 1840) were the twin daughters of Mr. and Mrs. Corcoran and younger sister of Brendan. Mary played with them often on the ship.
- Father Mullaney was the priest of Mary's church in Ireland. He gave her a blessing before she left.
- Mr. Nevin was a neighbor of the Driscolls who gave Mary a ride to Cork.
- Mr. (died May 26, 1847) and Mrs. O'Donnell (died June 7, 1847) were the parents of Alice. In 1847, they boarded a ship in hopes to join their daughter in America. On the ship, they looked after Mary who reminded them of their daughter. They both became ill and never recovered.
- Ruth Shattuck was a friend of Annie who also lived at the boardinghouse. She badly became ill but recovered and returned to work. One day, she "walked out" as she could no longer stand working at the mill.
- Sylvester Sawyer was a boy who worked at the mill. His finger was accidentally snapped off, but he returned to work a few days later.
- Dennis Kelly was Kate Driscoll's husband whom he married in 1851. They had two children.
- Silas Marks was Annie Clark's husband. They had no children together. He was a well-known lawyer in Racine, Wisconsin.