Final answer:
The Puritans sought to reform the Church of England from within, whereas the Pilgrims, who were Separatists, wanted a complete break from it, reflected in their different settlements, Plymouth for Pilgrims and Massachusetts Bay for Puritans.
Step-by-step explanation:
The key differences between the Puritans and the Pilgrims in early American history center on their relationship with the Church of England and their distinct settlements in North America. The Puritans, who established the Massachusetts Bay Colony, sought to reform the Church of England from within, while the Pilgrims, a subset of the Puritans and also known as Separatists, wanted to completely break away from the Church of England, which they accomplished when they settled Plymouth in 1620. Both groups shared a Calvinist Protestant foundation, but their approaches to dealing with what they viewed as corruption within the Church of England diverged significantly, with the Puritans aiming for reformation and the Pilgrims opting for separation.