The
United Church of Christ mainly descends from the Puritan churches of colonial New England. Most of those who didn't turn Unitarian ended up joining with a German Reformed group in creating the United Church of Christ in the mid 1900s.
Mark Dever got his start as a United Church of Christ minister at this congregation in Massachusetts:
http://topsfieldchurch.org/
Churches of Christ are one segment of the Restorationist Movement, a schism from Baptists in the 1800s:
http://www.leroygarrett.org/restorationreview/article.htm?rr18_04/rr18_04b.htm&18&4&1976
"Our original founders, the four pillars of our Movement, were all Presbyterians: Thomas and Alexander Campbell, Barton W. Stone and Walter Scott. But the masses that came into our ranks during the first generation, 1809-1830, were not Presbyterians but Baptists."
"Hundreds of these Baptist churches came into the Movement, as if by osmosis. They gradually imbibed 'Campbellism', as it was called, until they were no longer considered orthodox Baptist churches, and so they were dubbed 'Reformed Baptists'."
"These 'Reformed Baptists' finally lost all identification as Baptists and became known as 'Disciples of Christ', the name preferred by Alexander Campbell, but also as 'Church of Christ' and 'Christian Church'."