Dicey is the resourceful and fiercely independent 13-year-old leader of the Tillerman siblings. Often mistaken for a boy due to her short hair and practical clothing, she uses this to her advantage while guiding her siblings on foot across states. She shoulders the immense responsibility of keeping her family safe and fed, sacrificing her own childhood comforts to ensure their survival.

At 10 years old, James is the highly intelligent, academically gifted second-in-command of the siblings. He thinks critically about their survival and occasionally clashes with Dicey over leadership decisions. Though confident in a classroom setting, he relies heavily on his older sister for physical guidance and safety on the road.

Maybeth is a quiet nine-year-old girl with blonde hair and a beautiful singing voice. Adults often mistakenly assume she has severe learning disabilities due to her shyness and academic struggles in traditional environments. She possesses a gentle, observant strength and keeps her family connected through songs taught by their mother.

At six years old, Sammy is the youngest Tillerman sibling. He possesses a stubborn disposition and frequently slows the family's travel by refusing to walk or accept their new reality. He fiercely defends his mother's reputation from anyone who speaks ill of her, while his penchant for imaginative games brings a necessary spark of youth to the traveling group.

Abigail is the maternal grandmother of the Tillerman children, living entirely alone on a dilapidated farm in Crisfield, Maryland. Isolated and hardened by a history of domestic hardship, she initially presents a crotchety and highly uninviting exterior. She maintains a bountiful vegetable garden hidden behind her overgrown property, offering a physical representation of her concealed capacity to nurture.

A hostile landowner who initially agrees to pay the Tillerman children to harvest his tomatoes. He quickly reveals his true intentions by attempting to trap them on his property for free labor, utilizing a vicious dog to ensure they cannot run away.

Liza is the single mother of the four Tillerman children. Overwhelmed by financial ruin and severe mental health challenges, she reaches a breaking point and leaves her children in a Connecticut mall parking lot. Her sudden absence sets the entire narrative in motion as her children seek a place to belong.

Eunice is a devout Catholic factory worker living in Bridgeport, Connecticut. She recently lost her mother, Aunt Cilla, and dreams of formally entering the church to become a nun. When the Tillermans arrive unannounced at her doorstep, she takes them in out of a strict sense of religious duty rather than genuine familial affection.

Father Joseph is a Catholic priest who serves as Eunice's primary spiritual advisor. He approaches the children's situation practically and bureaucratically, organizing their summer schooling while strongly advocating for the younger siblings to be separated and placed into formal foster care.

Windy is a compassionate college student who notices the exhausted Tillerman children trying to survive on the streets. Having previously experienced running away from home himself, he brings the siblings to his dormitory, providing them with hot meals, dry clothes, and a safe place to sleep.

Stewart is Windy's college roommate who shares his space and resources to help shelter the Tillermans. When James steals money from his wallet, Stewart handles the situation with grace, choosing to teach the young boy a profound lesson about living as an honorable man rather than reacting with anger.

Edie is a teenage runaway currently hiding from her parents at a state park campsite. She travels with her companion, Louis, and frequently plays an autoharp, singing darker, harsher versions of the folk songs the Tillerman children know from their mother.

Louis is a runaway youth actively evading his parents. He shares his food with the Tillermans and openly expresses frustration over the lack of rights and autonomy afforded to children in society.

Jerry is a teenager whose parents work in politics. He and his friend Tom invite the Tillermans onto their father's sailboat and ultimately decide to transport the children across the bay, providing a massive shortcut for their journey.

Tom is Jerry's companion who assists in sailing the Tillerman children across the Chesapeake Bay to the Eastern Shore, allowing the siblings to avoid a dangerous walk over a massive bridge.

Will is a leader within a traveling circus. When the Tillermans run into his tent seeking safety, he claims them as his own to scare off their pursuer. He provides the children with temporary work and eventually drives them directly to Crisfield.

Claire works in the traveling circus performing with animals. She steps in without hesitation to physically protect the Tillerman children from the farmer, and later bonds with Sammy by teaching him how to participate in the dog performance routines.