A boy with an undiagnosed disorder, identifiable to modern readers as autism, who communicates nonverbally and is comforted by animals, often misunderstood by his community.

Katy's father, a compassionate doctor who respects Katy and teaches her about the human body, encouraging her to challenge societal norms.

Katy's kind and patient mother, who provides love and security to her family and neighbors, embodying traditional maternal roles.

The Thatchers' hired girl who is maternal and kind, providing comfort to Katy, and is fond of her brother Jacob.

Peggy's sister, who is ambitious and yearns for more than small-town life, willing to take risks to achieve her dreams.

A rebellious young man, expected to follow in his father's career path, who seeks freedom and defies his parent’s expectations.