Across the Wide Missouri

A rugged fur trapper who organizes the brigade and leads the dangerous trek into Blackfoot territory. He marries Kamiah partly for security and prestige, but he gradually falls in love with her, complicating his duties to keep the group safe. Throughout the expedition, he forges ties with Bear Ghost and confronts Ironshirt, learning that loyalty and leadership hinge on courage under fire.

Kamiah is the granddaughter of Blackfoot medicine man Bear Ghost and the adopted daughter of a Nez Perce chief. She guides the expedition through treacherous passes and becomes a bridge between two cultures. Her relationship with Flint deepens into love, but her fate is sealed by tribal conflict during the attack that claims her life.

Bear Ghost is a revered Blackfoot medicine man and leader who earns Flint's respect. He acts as a peacemaker and ally, returning horses and protecting his people. His death at the hands of Roy DuNord fuels revenge and shifts the balance of power within the region.

Ironshirt is a Blackfoot prince and war chief, driven to drive white trappers from his homeland. He sabotages the expedition, steals horses, and kills Bear Ghost's ally Baptiste DuNord and later nearly claims Chip's life. He finally confronts Flint in a climactic battle, meeting his end at Flint's hands.

Brecan is Flint's Scottish former trading partner who urges peace and proposes returning Kamiah to the Blackfoot. He frequently clashes with Flint's more aggressive plans and acts as a voice of caution. He fights to balance friendship with strategy, and his stance shapes the early fragile truce.

Pierre is a French Canadian trapper who joins the expedition, adding to the diverse mix of mountain men. He shares in the peril of the journey, trades, and alliances among the group.

Captain Humberstone Lyon is a seasoned Scotsman who fought at Waterloo and offers military discipline to the expedition. He supports Flint's leadership and contributes to the operation's organization and safety.

Looking Glass is a Nez Perce chief who adopts Kamiah and forms alliances with Flint. He emphasizes cautious diplomacy and stewardship of his people amid escalating tensions.