Donal is an eleven-and-a-half-year-old orphan with red hair, freckles, and a highly active imagination. Raised primarily by his grandmother at a rural Montana ranch cook shack, he must travel cross-country by bus alone when she requires surgery. He carries a beloved pair of moccasins, a purloined obsidian arrowhead, and an autograph book he hopes will gain him entry into Ripley's Believe It or Not. His quick wit and propensity for tall tales help him manage interactions with adult strangers.

Herman is a middle-aged, one-eyed retired sailor who lives with Aunt Kate in Wisconsin. Originally a German immigrant who worked shoveling coal on Great Lakes ore ships, he now spends his time smoking cigars in his greenhouse. He possesses a deep passion for western novels and lore, which forms an immediate bond between him and Donal.

Aunt Kate is Gram's estranged sister and Donal's temporary guardian in Wisconsin. She runs a strict, orderly household and holds rigid expectations for those around her. Disappointed by Donal's arrival and lack of refinement, she attempts to force him into her structured lifestyle, particularly by making him her canasta partner.

Gram is Donal's maternal grandmother and primary caregiver following the death of his parents. She works long hours as the cook for the Double W Ranch to support them both. Despite having only a third-grade education, she is deeply perceptive and holds high expectations for her grandson's behavior.

Rags is a world-champion saddle bronc rider and a larger-than-life figure in the western rodeo circuit. Known for his supreme confidence and distinctive attire, he has a reputation for riding untamable horses. He serves as an aspirational figure for Donal, embodying the rugged independence of the American West.

Wendell is the wealthy owner of the Double W Ranch in Montana. He strictly enforces property rules and views himself as the rightful owner of anything found on his land. He proudly displays artifacts, including the obsidian arrowhead Donal discovers, in a glass case inside his mansion.

Leticia, affectionately known as Letty, is an observant waitress relocating to Havre, Montana. She wears glasses, smokes, and uses a tough exterior to deter unwanted attention from men. She provides Donal with maternal warmth during his intimidating solo journey.

Harv is a large, rugged man with a talent for escaping from jail. Despite his outlaw status, he maintains a surprisingly calm demeanor and works various agricultural jobs across the West. He travels reluctantly under the custody of law enforcement.

Carl is a diminutive county sheriff tasked with transporting an escape-prone prisoner across Montana. He takes his law enforcement duties very seriously and grows highly suspicious of young Donal traveling alone.

Highpockets is the unofficial leader of a rough-looking group of migrant workers known as the "Johnson family." He organizes the men as they travel from harvest to harvest, determining who is trustworthy enough to join their ranks.

Jones is the pragmatic foreman of the Diamond Buckle Ranch. Tasked with assembling a competent crew for the late summer hay harvest, he tests prospective workers to ensure they can handle the demanding agricultural labor.

Smiley is a former rodeo clown turned ranch handyman. He possesses a highly disagreeable personality, frequently making crude remarks and causing friction among the other agricultural workers.

Louie is a member of the Blackfoot nation who sells Indigenous regalia and merchandise at regional festivals. He uses his resources and quick thinking to assist travelers who find themselves in sudden trouble.

Kerouac is a young, passionate author traveling west. Driven by a persistent literary muse, he spends his bus rides documenting his observations of life on the American road.

Dr. Schnieder is a medical professional stationed at a major national park. He provides care to tourists and locals alike, occasionally offering unexpected generosity to travelers in distress.

The Schneiders are a kind, elderly couple traveling by bus simply for the pleasure of vacations. They look out for younger passengers and represent the changing culture of mid-century leisure travel.

Ernie operates a local bar decorated to resemble the inside of a ship. He appreciates a good wager and serves as a reliable confidant for locals needing a break from their domestic lives.

Herta is an avid canasta player and part of Aunt Kate's social circle in Wisconsin. She owns a parakeet and takes her competitive card games very seriously, playing for money.

Fritz was a Great Lakes sailor who perished during a brutal autumn storm. Though deceased before the novel begins, his memory profoundly shapes the current living arrangements of his surviving loved ones.

Bud was Donal's father, a heavy equipment operator and World War II veteran who survived grave injuries on Omaha Beach. He died in a car accident, leaving his son in Gram's care.

Peg was Donal's mother, who met her husband while he worked on infrastructure projects in Montana. Her tragic death in an auto accident fundamentally changed her son's trajectory.