The First Church of Christ in Saybrook bills itself as the original church of the Saybrook settlement. According to the history section of the church's website, the present building - which dates from 1840 - is the fourth incarnation of a church first established in the small fort.
Church records are a bit scattered. Some of the church records are held by the Old Saybrook Historical Society, which does research for $10 per hour. Others are in publication form, accessible from a local bookstore. According to an article on American Ancestors, records are also part of the state church record index.