There are multiple themes depicted in Elizabeth George Speare's novel, The Witch of Blackbird Pond.
Perhaps the most prominent theme in the novel is that of personal identity. Given that the novel is a coming of age text, which follows the trials and tribulations of the protagonist, Kit, struggles to define not only who she is, but who she believes she should be.
Another theme depicted in the novel is an individual's duty to community. At times in the novel, the duty of the individual infringes on a character's ability to self-define.
Two themes, which go hand-in-hand, relevant to the novel are those of change and continuity. Given that these forces either work against each other or with each other, the characters in the novel are constantly struggling to find out if their own history needs to influence a change in them or help to define them for good.
Transcendence is another theme ever present in the novel. Kit is moved by her experiences with nature and its impact upon her life. It seems that when she "interacts" with nature, something in her life has changed (or is transcended).
One final theme from the novel is the impact of religion. Puritanism lies at the core of the novel. Puritans were very strict about their ways of life and their ideologies. Their days were to be spent doing one of three things: working, praying, or reading the Bible. Ant actions a person took which were not deemed holy, the person, typically, would be considered a heretic. The fact that Kit does not feel a true tie to her own religion, both the Puritan way of life and her own religious identity, forces the theme of religion to be one of an overwhelming nature (for both Kit and engaged/sympathetic readers).