The Roman Catholic Diocese of Rockville Centre (Latin: Dioecesis Petropolitana in Insula Longa) is a Latin Church ecclesiastical territory or diocese of the Catholic Church that comprises the territory of Nassau and Suffolk counties on Long Island in the U.S. state of New York, except for Fishers Island, which is part of Suffolk County but is included in the Diocese of Norwich, Connecticut. Founded in 1957, this diocese was created from territory that once belonged to the Diocese of Brooklyn. As of 2005[update], it the sixth-largest Catholic diocese in the United States, currently serving approximately 1.5 million people in 134 parishes. The diocese is named for the village where its cathedral, St. Agnes Cathedral, is located, Rockville Centre in Nassau County. The fifth and current bishop is John Barres. The Diocese of Rockville Centre is a suffragan diocese in the ecclesiastical province of the metropolitan Archdiocese of New York.
