Came across this in my research, when seeking the head of the Cestui Que Vie Trust court system for Michigan, who could give procedural direction to the maritime (ecclesiastical/canon law) Court priests for securing the release of MP's body. The word metro-politan (METRO) popped out. This first reference is from Wikipedia, but the second is an official Catholic reference.
The Roman Catholic Archdiocese of Detroit (Latin: Archidioecesis Detroitensis) is an archdiocese of the Latin Rite of the Catholic Church covering (as of 2005) the Michigan counties of Lapeer, Macomb, Monroe, Oakland, St. Clair, and Wayne. It is the metropolitan archdiocese for the Roman Catholic Ecclesiastical Province of Detroit, which includes all dioceses in the state of Michigan. In addition, in 2000 the archdiocese accepted pastoral responsibility[2] for the Roman Catholic Church in the Cayman Islands, which consists of Saint Ignatius Parish[3] onGrand Cayman (the Archdiocese of Kingston maintains a mission sui iuris jurisdiction over the Cayman Islands).[4]
Established as the Diocese of Detroit on March 8, 1833, it was elevated to Archdiocese on May 22, 1937. Ste. Anne's in Detroit is the second oldest continuously-operating Roman Catholic Parish in the United States dating from July 26, 1701.[5][6]
An ecclesiastical province (or churchly province) is a large jurisdiction of religious government, so named by analogy with a secular province, existing in certain hierarchical Christian churches, especially in the Catholic Church (both Latin and Eastern Catholic) and Orthodox Churches and in the Anglican Communion. In the early church, and in some modern churches, its chief city and seat is called a metropolis and its bishop is called a metropolitan.
At the First Council of Nicaea (325) this position of the metropolitan was taken for granted, and was made the basis for conceding to him definite rights over the other bishops and dioceses of the state province. In Eastern canon law since the fourth century (cf. also the Synod of Antioch of 341, can. ix), it was a principle that every civil province was likewise a church province under the supreme direction of the metropolitan, i.e. of the bishop of the provincial capital.
http://www.newadvent.org/cathen/10244c.htm
Catholic encyclopedia
Metropolitan, in ecclesiastical language, refers to whatever relates to the metropolis, the principal city, or see, of an ecclesiastical province; thus we speak of a metropolitan church, a metropolitan chapter, a metropolitan official, etc. The word metropolitan, used without any qualificative, means the bishop of the metropolitan see, now usually styled archbishop. The term metropolite (Metropolites,Metropolita) is also employed, especially in the Eastern Churches (see ARCHBISHOP). The entire body of rights and duties which canon law attributes to the metropolitan, or archbishop as such, i.e., not for his own diocese, but for those suffragan to him and forming his ecclesiastical province, is called the metropoliticum.