The Congregational Christian Churches were a Protestant Christian denomination that operated in the U.S. from 1931 through 1957. On the latter date, most of its churches joined the Evangelical and Reformed Church in a merger to become the United Church of Christ. Others created the National Association of Congregational Christian Churches or joined the Conservative Congregational Christian Conference that formed earlier in 1945. During the forementioned period, its churches were organized nationally into a General Council, with parallel state conferences, sectional associations, and missionary instrumentalities. Congregations, however, retained their local autonomy and these groups were legally separate from the congregations.