Erzbistum Hamburg) is a Latin Church ecclesiastical territory or diocese of the Catholic Church in the north of Germany and covers the Federal States of Hamburg and Schleswig-Holstein as well as the Mecklenburgian part of the Federal State of Mecklenburg-Vorpommern.

[1] In 831, Hamburg was elevated to an archbishopric by Pope Gregory IV and in 834 the Benedictine monk Ansgar was elected as the first archbishop.

During the Reformation the bishopric underwent steady deterioration and finally, with the Peace of Westphalia in 1648, it ceased to exist.

By the apostolic constitution Omnium Christifidelium of Pope John Paul II, of October 24, 1994 coming into effect on January 7, 1995, the archdiocese of Hamburg was erected again.

Today it consists of territory that once belonged to the dioceses of Osnabrück, and Hildesheim, namely the Free and Hanse-City of Hamburg, the State of Schleswig-Holstein and the half-State of Mecklenburg.