The Evangelical Congregational Church of Grafton traces its roots back to a church which had been established in 1671 by Rev. John Eliot, or one of his pupils, in an area known as the Hassanamisco Plantation (now known as the Hassanamesit Reservation). The membership of this church was entirely of Native Americans belonging to the Hassanamisco Nipmuc; at the time there was only one other such church in Massachusetts. The church continued through the early and mid-1670s until it was destroyed during King Philip’s War, along with much of the Hassanamisco tribe. In 1698, the Report of Commissioners counted five families living on the Hassanamisco Plantation. During the early 1700s, there was interest from European settlers to buy the plantation from the Hassanamisco and in 1727 the General Court of Massachusetts gave permission for the sale of 7,500 acres of land for the price of £2,500 to 40 English settlers. The “Church of our Lord Jesus Christ at Hassanamisco” was established on December 28, 1731, with the Rev. Solomon Prentice as the its pastor, and construction of the first meeting house was completed by the spring of that year. The town of Grafton was later incorporated in 1735 and the church was then known as the Church of Christ in Grafton.

After 1740, Rev. Prentice became a follower of George Whitefield. This led to a prolonged conflict between Prentice and his parish. Multiple ecclesiastical councils were called between 1744 and 1747 until the council dismissed him of his pastoral duties on the 10th of July, 1747. He was replaced by the Rev. Aaron Hutchinson who served the church from 1750 to 1772. Hutchinson was followed by the Rev. Daniel Grosvenor (1774-1778) and Rev. John Miles (1796-1826). Rev. Moses C. Searle served as pastor from 1826 to 1832. Under his pastorate, the church admitted 162 new members and built a Sunday school; however, the end of his pastorate also saw the separation of the church into two. In 1831, the majority of the church’s members voted to dismiss Searle for his introduction of a doctrinal creed into the church which limited those who could be admitted. This vote of dismissal led to the eventual succession of Orthodox members in 1832 who formed their own church, the Evangelical Congregational Church. The remaining Unitarian members reformed the Church of Christ into the Congregational Church of Grafton.

These two churches served the Grafton communities throughout their separate histories. In 1931, the two churches held a joint bicentennial celebration. The Evangelical Congregational Church was renamed, in 2011, Congregational Church of Grafton, UCC. This church continues to serve the Grafton community today. The Unitarian church also continues to serve the Grafton and Upton communities as the Grafton-Upton Unitarian Universalist Societies.