The First Congregational Church of Litchfield collection provides documentation on the church from 1845-1999, although the church was founded in 1721. The collection brings together records given by the church and a number of other donors, and includes annual reports; addresses, sermons, and discourses; several editions of the church manual and membership roll; Sunday School Library catalogue (1859) and records; histories; photographs; financial records; correspondence; and other records. There is extensive documentation of the church's colonial revival restoration, 1926-1930, including architectural plans, drawings, notes, bids, correspondence, and related papers.
The First Congregational Church of Litchfield was founded in 1721. Its first minister was Timothy Collins, who served until 1751. Noted clergyman Lyman Beecher was the church's minister from 1810 to 1826. The first church building was constructed in 1723 or 1724 and was replaced by a new structure in 1761. A third church was built in 1829 north of the green. This building was moved and replaced in 1873 with a Gothic structure. In 1929, as part of the colonial revival movement in Litchfield, the 1829 church—which had been reused as an assembly hall and movie theater—was returned to the site and restored under the supervision of architect Richard H. Dana.
The church's business and legal affairs were managed by the First Ecclesiastical Society, which was founded in 1768. The church itself was incorporated in 1907 and in 1941 the two entities were combined into one corporation. In 1960, the church became part of the United Church of Christ.