The Diocese of Oakland is a Latin Church ecclesiastical territory, or diocese, of the Catholic Church in the San Francisco Bay Area of California in the United States. It is a suffragan diocese in the ecclesiastical province of the metropolitan Archbishop of San Francisco.

The Archdiocese of San Francisco is a Latin Church ecclesiastical territory or diocese of the Catholic Church in the northern California region of the United States. The Archdiocese of San Francisco was erected on July 29, 1853, by Pope Pius IX and its cathedral is the Cathedral of Saint Mary of the Assumption.