The English Pilgrims and Puritans, who were the first Europeans to settle New England, established a church in each of their communities, including Wethersfield. Theologically, these were Protestant churches influenced by the teaching of John Calvin and the Puritan movement in England. Because ultimate governing authority for these churches was, and usually still is, vested in the church's congregation, they became known as Congregational churches.

Although Congregational churches were legally independent in Connecticut, until 1818, they had some government support, and their clergy met often and worked together to form new churches and on projects such as sponsoring missionaries. There also were gatherings of area congregants and large gatherings of Congregationalists that resulted in documents like the Cambridge Platform. Thus, Congregational churches, while legally independent, remained united on significant questions of faith and polity prior to 1871, when the National Council of Congregational Churches came into being as an organized denomination in which these churches, including Wethersfield's First Church, participated.