The parish was formed in 1714 when what is now Littleton was organized as Nashoba Plantation. The first minister was Benjamin Shattuck, who served for a time as a lay minister and then was ordained here on Christmas Day, 1717. At that time there was only one church in town, the town church. 

In 1822, Baptists in town decided to create their own society and build a church. At that point, Unitarianism was just beginning in this country. 

In 1840, the congregation was equally divided between "orthodox congregationalists" and those who were more influenced by the humanists, utopians, and unitarians of the time. In a very amicable separation, the orthodox congregationalists left to form their own society. Also at that time, monetary support from the town ended - the separation of church and state was becoming a reality in Littleton (although the town bylaws still require that the warrant for any Town Meeting be posted at all the churches in town). 

In the 1840's, the word "Unitarian" begins to appear in church records. By the end of that decade, the church affiliated with the American Unitarian Association. A variety of names combining both "Congregational" and "Unitarian" were used until the church finally settled on "First Church Unitarian, Littleton" as its official name. 

The church has played a central role in the history of the town of Littleton. Many historical artifacts and documents from the church are on permanent loan to the Littleton Historical Society . We retain church records dating back to 1755.