Anna
Anna is the narrator of the story and though her specific age is never given, the reader can easily deduce from context and connotation that she is either on the verge of becoming a teenager or has just barely arrived there. Having to take over household chores like cooking meals is not the only reason that Anna is experiencing a very deep emotional emptiness at the loss of her mother. Her mother died as a result of giving birth to her younger brother Caleb which has had the effect of loosening the natural emotional bond between siblings.
Caleb
There is a gap of about five years between the ages of Anna and Caleb, making her younger brother about eight years old. The resulting emotional state of Caleb in the wake of his mother dying when he was just one day old is one of overwhelming abandonment issues. Always on the lookout for signs that he may be abandoned by those around him, Caleb is especially aware of any indication of unhappiness on the part of Sarah once she joins the family. Acutely sensitive to the fact that he could lose someone close to him at any time and without warning or sense, Caleb is constantly making inquiries of Sarah on the subject of her plans and current state of mind.
Jacob
Father to Anna and Caleb, Jacob tries to run his farm and care for his animals as best he can while raising children without a wife. Jacob works very hard and that diligence is equaled by his care and concern for his children to grow up as close to possible as they would have if his wife were still alive. Such a desire has inescapable built-in limitations, however, and those limitations are tested by dipping his toe into the strange waters of mail-order bride opportunities. Even so, Jacob is willing to sacrifice his own needs to preserve the integrity of his family and will not submit to asking Sarah to come all the way to the prairie from her home in Maine without the express vocal consent of both Anna and Caleb.
Sarah Wheaton
Sarah describes herself as strong, a hard worker and not particularly mild of manner. Or, in other words, very much a stereotypical Yankee woman from Maine. It is her response to a personal advertisement in the newspaper for a companion to the widowed Jacob who can take on the roles normally reserved for mother to his two children that brings her into the orbit of Jacob and his family. Sarah proves herself more than capable of standing up to Jacob, revealing both a stubborn streak of independence while also occasionally demonstrating endearing acts of pure femininity. These two disparate sides serves to make the physically plain Sarah stand tall in the community that sometimes looks upon her independent side in a way that questions the suitability of her more domestic side as something more than mere companion to Jacob.
