Henry is the 14-year-old eldest sibling of the orphaned Alden family. Smart and capable, he steps into a fatherly role to provide for his younger brother and sisters. He works at odd jobs in Silver City, earning money for food and supplies while keeping his family's identity hidden.

Jessie is the 12-year-old sister who acts as a mother figure to the younger Alden children. She organizes the group's daily life and devises clever solutions to everyday problems, like building a broom from sticks and a milk refrigerator in the brook. Her protective instincts keep the family focused and secure in their woodland camp.

Violet is the 10-year-old Alden sister, described as having brown hair and brown eyes. Though shy, she works hard alongside Jessie to improve their boxcar home by hemming a tablecloth and gathering stones. She acts as a bridge between the older siblings' serious responsibilities and her younger brother's playful energy.

Benny is the enthusiastic five-year-old youngest member of the Alden family. Friendly and endearing, he charms adults easily and provides lighthearted moments for his older siblings. He eagerly helps with chores, like hauling rocks in his custom-made cart, and learns to read using ash from the fireplace.

Dr. Moore is a physician living in Silver City with his mother. He hires Henry for household chores and quickly recognizes the boy's strong work ethic. Observant and patient, he watches over the children from a distance, choosing to ensure their safety without immediately interfering in their independent life.

James Henry Alden is a wealthy mill owner from Greenfield. He offers a large reward for information about his four missing grandchildren. Known to possess immense resources and a powerful personality, he looms over the children as a frightening figure. The orphans actively hide from him, believing he is a cruel man who disapproved of their mother.

Watch is a medium-sized dog, likely an Airedale, who arrives at the children's camp injured. After Jessie removes a thorn from his paw, he adopts the children as his own pack, serving as their loyal guardian and friend. His presence provides the orphans with an extra layer of security in the woods.

Mrs. Moore is Dr. Moore's mother, who lives with him in a nice neighborhood in Silver City. She is a wise and kind woman who happily supplies Henry with leftover vegetables for his family. She supports her son's cautious approach to checking on the children and shares his desire to protect them.

The Baker runs a shop in a town near where the children originally lived. Along with his wife, he plots to exploit the older orphans for free labor while planning to send the youngest sibling away to a children's home.

The Baker's Wife works at the bakery and reluctantly allows the orphans to sleep on the shop's benches. She intends to keep the older children as unpaid workers while forcing the youngest into an orphanage, prompting their midnight escape into the woods.