Claim: First Church in Charlestown is a Congregational church that became a member of the Southern Baptist Convention, and is a part of the 9 Marks (Center for Church Reform) Network.
Evidence: It is dually aligned with both the United Church of Christ and the Southern Baptist Convention, holding to a conservative view of the Bible and holding to the traditional Reformed view of theology. The church is also a part of The Gospel Coalition and 9 Marks networks, as well as one of the cohort churches in Overseed, an organization dedicated to reviving historic New England churches, by returning them to a Gospel preaching view of theology. 
Mark E. Dever (born August 28, 1960) is the senior pastor of the Capitol Hill Baptist Church in Washington, D.C., and the president of 9Marks (formerly known as the Center for Church Reform), a Christian ministry he co-founded "in an effort to build biblically faithful churches in America."