The Episcopal Church is governed by a General Convention and consists of 100 dioceses in the United States proper, plus ten dioceses in other countries or outlying U.S. territories and the Convocation of Episcopal Churches in Europe, which is similar to a diocese.
Each is led by a bishop. A diocese includes all the congregations within its borders, which usually correspond to a state or a portion of a state. Some dioceses includes portions of more than one state. For example the Diocese of Washington includes Washington, D.C. and part of Maryland.
The naming convention for the domestic dioceses, for the most part, is after the state in which they are located or a portion of that state (for example, Northern Michigan or West Texas).
Usually (though not always), in a state where there is more than one diocese, the area where the Episcopal Church (or Church of England before the American Revolution) started in that state is the diocese that bears the name of that state. For example, the Church of England's first outpost in what is now Georgia was in Savannah, hence the Diocese of Georgia is based in Savannah.
There are, however, many dioceses named for their see city or another city in the diocese. A few are named for a river, island, valley or other geographical feature. The list below includes the see city in parentheses if different from the name of the diocese or unclear from its name.
The see city usually has a cathedral, often the oldest parish in that city, but some dioceses do not have a cathedral. The dioceses of Iowa and Minnesota each have two cathedrals. Occasionally the diocesan offices and the cathedral are in separate cities.
The dioceses are grouped into nine provinces, the first eight of which, for the most part, correspond to regions of the U.S. Province IX is composed of dioceses in Latin America. Province II and Province VIII also include dioceses outside of the U.S.