About the PCA About PCA Riveroaks is a member of the denomination, Presbyterian Church in America. The PCA is one of the faster growing denominations in the United States, with over 1400 churches and missions throughout the USA and Canada. There were over 340, 000 communicant and non-communicant members as of 2008. Being a "reformed" denomination refers to the fact that the Holy Spirit is continuing to "re-form us as new creatures" through the process of growing more holy (sanctification ) in the Lord. It also refers to the doctrines of Scripture that were rediscovered during the time of the Reformation.