English dioceses tend to be named from the see city in which the bishop's chair (cathedra) is located within the principal church (cathedral). Thus: the Diocese of London, the Diocese of Durham, the Diocese of Salisbury.

American dioceses tend to be named after the state in which they are located. Thus, the Diocese of New York, the Diocese of California, the Diocese of Tennessee.

Some American states contain more than one diocese and have oddly geopgraphic names. Thus the Diocese of Upper South Carolina and the Diocese of Western North Carolina.

Some have more interesting names, based on their history. Thus, the Diocese of El Camino Real and the Diocese of Rio Grande.

When the Diocese of Olympia was carved out of the Washington Territory, it was assumed that the see city would be the state capital: Olympia. Those who named the diocese were wrong about this, as the see ended up in Seattle.

The City of Olympia was named after the nearby Olympic Mountains, which were named after the home of the Greek gods.