The National Council of Congregational Churches of the United States was a mainline Protestant, Christian denomination in the United States. Its organization as a denomination was delayed by the Civil War. Congregational leaders met again in Boston, Massachusetts in 1865, where they began to hammer out standards of church procedures (polity) and adopted a statement of faith, known as the Burial Hill Declaration. Denominational organization came in 1871 with formation of the National Council of Congregational Churches, which existed until its merger in 1931. In 1928, there were 5,497 Congregational churches in the U.S. with a membership of 939,130. These churches were served by 5,648 ministers.