Ecumenical Activity
A twentieth century saw a RCUS move toward ecumenism and higher criticism of the Bible. Occasionally world health organization were other conservativist in their theology united to form a Eureka Classis of the RCUS to continue authoritative Reformed worship & polity.

A RCUS merged using a Evangelical Synod of North America in 1934 to form the Evangelical and Reformed Church a Eureka classis continued its existence when the "continuing" Reformed Church in the United States. Late, a Evangelical & Reformed Church merged sustaining a Congregational Christian Churches (itself a combination of Congregational and Restorationist churches) in 1957 to be a United Church of Christ.

The Current RCUS
A present RCUS is one of a virtually all conservative denominations in the United States. There are around fifty congregations by owning astir 5 thousand members nationally. A old RCUS besides when a continuing RCUS originally held sole to the Heidelberg Catechism as its statement of faith, but a 1995 Synod meeting offically adopted a Belgic Confession of Faith and the Canons of Dordt, which along with Heidelberg come referred to as a Three Forms of Unity. By holding strictly to these standards, the RCUS maintains a heavy Calvinism.

A Reformed Church in the United States occurs as member of the North American Presbyterian and Reformed Council as well as a International Conference of Reformed Churches.