The Presbyterian Church (USA), abbreviated PC(USA), is a mainline Protestant denomination in the United States. It is the largest Presbyterian denomination in the US, and known for its liberal stance on doctrine and its ordaining of women and members of the LGBT community as elders and ministers. The PC(USA) was established by the 1983 merger of the Presbyterian Church in the United States, whose churches were located in the Southern and border states, with the United Presbyterian Church in the United States of America, whose congregations could be found in every state. The similarly named Presbyterian Church in America is a separate denomination whose congregations can also trace their history to the various schisms and mergers of Presbyterian churches in the United States. Unlike the PCA, the PC(USA) supports the ordination of women and affirms of same-sex marriage. It also welcomes practicing gay and lesbian persons to serve in leadership positions as ministers, deacons, elders, and trustees. The denomination had 1,193,770 active members and 18,458 ordained ministers (including retired) in 8,813 congregations at the end of 2021. This number does not include members who are baptized but who are not confirmed or the inactive members also affiliated. For example, in 2005, the PC(USA) claimed 318,291 baptized, but not confirmed, members and nearly 500,000 inactive members in addition to active members. Its membership has been declining over the past several decades; the trend has significantly accelerated in recent years, partly due to breakaway congregations. Average denominational worship attendance dropped to 423,721 in 2021 from 748,774 in 2013. The PC(USA) is the largest Presbyterian denomination in the United States. History Origins Presbyterians trace their history to the Protestant Reformation in the 16th century. The Presbyterian heritage, and much of its theology, began with the French theologian and lawyer John Calvin (1509–64), whose writings solidified much of the Reformed thinking that came before him in the form of the sermons and writings of Huldrych Zwingli. From Calvin's headquarters in Geneva, the Reformed movement spread to other parts of Europe. John Knox, a former Roman Catholic priest from Scotland who studied with Calvin in Geneva, took Calvin's teachings back to Scotland and led the Scottish Reformation of 1560. Because of this reform movement, the Church of Scotland embraced Reformed theology and presbyterian polity. The Ulster Scots brought their Presbyterian faith with them to Ireland, where they laid the foundation of what would become the