Esther is the eldest resident of Apple Island and the matriarch of the Honey family. She carries deep trauma from an abusive past, which fuels her intense suspicion of white mainlanders and government officials. She acts as the primary keeper of the island's oral history, frequently recounting the story of her ancestors surviving a devastating flood. She fiercely protects her grandchildren and clearly recognizes the prejudice directed at her community.

Ethan is Esther's grandson and Eha's son, a highly talented young artist whose light skin allows him to pass as white in mainland society. He receives art supplies from the relief society and studies under Matthew Diamond. When he is offered a chance to study art on a Massachusetts estate, he experiences life outside the island for the first time, leading to profound culture shock and an exploration of his identity.

Matthew is a white teacher and preacher from the mainland who visits Apple Island every summer. He views himself as a savior to the impoverished community, taking a special interest in the gifted children. However, his reports and calls for aid invite devastating government scrutiny and eugenics committees to the island.

Bridget is a young Irish immigrant employed at a sprawling mainland estate. She experiences intense homesickness for her own island home across the Atlantic. When Ethan arrives to paint in the estate's barn, she becomes intrigued by his process, and the two young outsiders form a strong emotional connection.

Eha is Esther's son and the father of Ethan, Tabitha, and Charlotte. He is a quiet, diligent carpenter who struggles to articulate his thoughts verbally but processes the world through his physical labor. He relies on the guidance of Zachary Hand to God Proverbs and slowly steps into a leadership role as outside forces threaten the island.

Zachary is an elderly, formerly enslaved carpenter who found sanctuary on Apple Island after the Civil War. He lives inside a hollowed-out tree, treating it as both his home and his life's artistic masterpiece. He acts as the moral foundation of the community, holding onto immense anger at the prejudice of the mainland while counseling peace among the islanders.

Theophilus is a member of the impoverished Lark family who subverts traditional gender roles by managing domestic duties. He wears his grandfather's apron and his mother's threadbare gingham dress, honoring his family's history through his daily attire.

Candace is the primary provider for the Lark household, spending her days fishing in the channel. She wears men's clothing and keeps her hair short, successfully sustaining her four children through hard physical labor.

Rabbit is the independent daughter of Theophilus and Candace Lark. She rarely speaks and does not attend the island's makeshift school, preferring to live entirely off the land and roam freely.

Benjamin is the historical patriarch of Apple Island. As a formerly enslaved man and skilled carpenter, he established the settlement by planting an apple orchard to honor the memory of his mother.

Patience is the Irish wife of Benjamin Honey and the original matriarch of the island. She is celebrated in family myth for sewing a diverse, patchwork flag and raising it during a devastating flood to save her remaining family.

Thomas Hale is a wealthy Massachusetts estate owner who agrees to patronize Ethan's art education. He values high society and order, enforcing strict rules of conduct upon his domestic staff.

Iris is an unmarried woman in her forties who lives on the north end of Apple Island. She earns money by washing clothes for mainlanders and helps raise three abandoned children, fiercely defending her home against government inspectors.

Violet lives with her sister Iris and helps manage their washing business. She assists in caring for the Sockalexis children and maintains a quiet resistance against the intrusion of mainland authorities.

Tabitha is the daughter of Eha and sister to Ethan. She spends her days playing along the channel and listening to the rich oral history of her family.

Charlotte is Eha's daughter and Ethan's sister. Like Tabitha, she represents the youngest generation of the Honey family living in isolation on Apple Island.

Annie is a solitary woman who resides away from the main cluster of families. She is fiercely independent and generally avoids interaction with both her neighbors and the mainland authorities.