The Episcopal Diocese of Duluth was a diocese

Diocese

A diocese is the district or see under the supervision of a bishop. It is divided into parishes.An archdiocese is more significant than a diocese. An archdiocese is presided over by an archbishop whose see may have or had importance due to size or historical significance...

 of the Episcopal Church in the United States of America.
The diocese was created as the Missionary Diocese of Duluth in 1895 as a result of the division of the Diocese of Minnesota

Episcopal Diocese of Minnesota

The Episcopal Diocese of Minnesota is the diocese of the Episcopal Church in the United States of America which has jurisdiction over all of Minnesota, except Clay County, which is in the Episcopal Diocese of North Dakota, and Browns Valley, which is in the Episcopal Diocese of South Dakota. It is...

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It elected its first bishop in 1896 and became the Diocese of Duluth in 1907. The diocese reunited with the Diocese of Minnesota in 1943.

Bishops of the Diocese

• James Dow Morrison Missionary Bishop (1896–1906), Diocesan bishop
  Diocesan bishop
  A diocesan bishop — in general — is a bishop in charge of a diocese. These are to be distinguished from suffragan bishops, assistant bishops, coadjutor bishops, auxiliary bishops, metropolitans, and primates....
  
   (1907–1921)
• Granville Gaylord Bennett (1921–1933)
• Benjamin Tibbets Kemerer (1933–1943)