This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
The National Council of Churches did not appear out of nothing in 1950. It absorbed an older body that had already been trying to hold American Protestantism together for four decades. The Federal Council of Churches formed in 1908, in the middle of the disruptions of rapid American industrialization, as denominations that competed for members on Sunday found they had shared interests to defend on Monday, particularly on questions of labor and social welfare that no single church could press alone. By the late 1940s the Federal Council was one of several overlapping national ecumenical bodies working on adjacent problems, education, missions, Christian unity, each with its own council and its own overhead.
In 1950, meeting in Cleveland, those bodies merged into a single organization, the National Council of Churches, folding the Federal Council's advocacy work into a broader structure built around program commissions rather than separate agencies. What began with twenty-nine member communions has grown since to roughly three dozen, spanning mainline Protestant, Eastern and Oriental Orthodox, African American and historic peace church traditions, representing tens of millions of American Christians under a single ecumenical umbrella that now operates from Washington, D.C.