* Laura Ingalls Wilder: The protagonist and narrator of the story, Laura is a curious and adventurous young girl.
* Mary Ingalls: Laura's older sister, Mary is kind and gentle but also has a strong sense of responsibility.
* Pa Ingalls: Laura's father, Pa is a resourceful and loving man who works hard to provide for his family.
* Ma Ingalls: Laura's mother, Ma is a patient and loving woman who manages the household and cares for her children.
* Carrie Ingalls: Laura's younger sister, Carrie is a playful and energetic child.
* Charles Ingalls: Laura's younger brother, Charles is a mischievous and adventurous boy.
The book also features several important supporting characters, including:
* Mr. Edwards: The kind and helpful owner of the Plum Creek homestead.
* Mrs. Edwards: Mr. Edwards' wife, who is warm and welcoming to the Ingalls family.
* Nellie Oleson: A wealthy and snobbish girl who often tries to put Laura down.
* Willie Oleson: Nellie's younger brother, who is often teased by Laura and her brothers.
* Mr. and Mrs. Oleson: Nellie and Willie's parents, who are wealthy but often unkind to the Ingalls family.
While the Ingalls family is the central focus of the story, "On the Banks of Plum Creek" also explores the relationships between these characters and their neighbors, friends, and enemies.