United Presbyterian Church in the United States of America

The United Presbyterian Church in the United States of America (UPCUSA) was the largest branch of Presbyterianism in the United States from May 28, 1958, to 1983. 
It was formed by the union of the Presbyterian Church in the United States of America (PCUSA) with the United Presbyterian Church of North America (UPCNA) in Pittsburgh Pennsylvania, in May 1958.
In 1983, the vote was finally held regarding the merger, with a unanimous 151 presbyteries in the UPCUSA affirming it, and the PCUS affirming it 53 to 8. On June 10, 1983, the first General Assembly was held for the new denomination, which would be called the Presbyterian Church (USA).