The Mennonite Church USA, is an Anabaptist Christian denomination in the United States. The abbreviation, MCUSA is not officially used by the denomination because of the confusion with MCC US, another Anabaptist organization. Although the organization is a recent 2002 merger of the Mennonite Church and the General Conference Mennonite Church, the body has roots in the Radical Reformation of the 16th century. Total membership in Mennonite Church USA denominations decreased from about 133,000, before the merger in 1998, to a total membership of 120,381 in the Mennonite Church USA in 2001. In 2013 membership had fallen to 97,737 members in 839 congregations. In 2016 it had fallen to 78,892 members.