I thought the Reform Church was now part of the UCC.
These churches are from the Reformed Church in America. The UCC was formed by a merger of the Congregationalist Christian Church and the Evangelical and Reformed Church. The “Reformed” part of the E&R was from the Reformed Church in the United States. Some of the RCUSA did not join the E&R and that denomination evidently still exists.
The Reformed who went into the UCC were of German origin. The Reformed Church in America is of Dutch origin.