It covers the city of Superior and the following Wisconsin counties: Ashland, Barron, Bayfield, Burnett, Douglas, Iron, Lincoln, Oneida, Price, Polk, Rusk, Sawyer, St. Croix, Taylor, Vilas, and Washburn.

When French explorer Jean Nicolet entered the Green Bay areas in 1634, he was followed by Jesuit missionaries.

[4] In 1669, Reverend Jacques Marquette arrived at the mission after Allouez moved to the Fox River Valley.

Allouez celebrated Mass with a Native American tribe near present-day Oconto, Wisconsin in December 1669, the feast of St. Francis Xavier.

The mission moved to Red Banks for a short time in 1671, and then to De Pere, where it remained until 1687, when it was burned.

The missionaries worked with the Fox, Sauk, and Winnebago tribes, protected by Fort Francis near Green Bay.

[2] When the British took control of New France in 1763 after the French and Indian War, the bishops in Quebec continued to have jurisdiction in the Wisconsin region.

It covered all the American states and the Northwest Territory, which included part of present-day Wisconsin.

In 1836, Reverend Frederic Baraga arrived at La Pointe and built a log church to re-established St. Joseph's Parish.

In 1918, during World War I, the US Department of Justice investigated Koudelka; some diocesan priests had accused him of being pro-German.

After speaking with Koudelka and viewing some of his writings that supported US involvement in the war, the investigators concluded that these accusations were groundless.

When he learned that a local community of sisters was living in an overcrowded residence, he remodeled the house and quietly turned it over to them.

[18] To replace Pinten, Pope Pius XI in 1926 named Theodore H. Reverman of the Archdiocese of Louisville as the next bishop of Superior.

Pope Pius XII then selected Reverend William O'Connor of Milwaukee as bishop of Superior.

During his tenure as bishop, O'Connor founded three new parishes, opened two new schools, and erected ten units of the Confraternity of Christian Doctrine with a total enrollment of 12,000 children.

[22] Pope John XXIII selected Reverend George Hammes from La Crosse as the next bishop in 1960.

[23] Pope John Paul II named Reverend Raphael Fliss from Milwaukee as coadjutor bishop for the diocese in 1979 to assist Hammes.

Later that year, Pope Benedict XVI named Reverend Peter Christensen of the Archdiocese of Saint Paul and Minneapolis as bishop of Superior.

[25] Reverend Lawrence Murphy, director of the St. John's School for the Deaf in St. Francis, Wisconsin, was forced to resign his position in 1974 due to complaints of sexual abuse of students.

[26] Two men from Boulder Junction reported abuse by Murphy during this time period to the diocese.

[29] The parents of a 14-year-old boy accused Reverend David Malsch in 1991 of sexually assaulting their son in a swimming pool and taking nude pictures of him.

[33] In February 2002, Reverend Ryan Erickson shot and killed James Ellison and Daniel O'Connell at a funeral home in Hudson.

The Ellison family sued the diocese in 2006, saying that diocesan officials knew about Erickson's erratic behavior before the shootings.

[35] Reverend Tom Ericksen was arrested in Minneapolis, Minnesota in November 2018 on a warrant from Sawyer County.