On July 5, 1840, Jesuit missionary Pierre-Jean De Smet offered the first mass in the Wyoming area, east of the present-day town of Daniel.

[2] In 1851, John Miège was installed in a ceremony in St. Louis as vicar apostolic for the Indian Territory east of the Rocky Mountains.

[4] In 1859, Pius IX named James O'Gorman, prior of New Melleray Abbey, near Dubuque, Iowa, as the vicar apostolic.

In 1875, Cusson persuaded the Sisters of Charity of Leavenworth to come to Laramie, where they opened a hospital in a house donated by the Union Pacific Railroad.

The Apostolic Vicariate of Nebraska was elevated to the Diocese of Omaha by Pope Leo XIII on October 2, 1885.

[7] Burke faced attacks by the American Protective Association, an anti-Catholic and anti-Irish hate group.

Burke traveled to Rome to petition the Vatican to attach the diocese to a more established one, citing the dire conditions in Wyoming.

On December 18, 1896, Thomas Lenihan of the Archdiocese of Dubuque was named the second bishop of the Diocese of Cheyenne by Leo XIII.

[12] On June 10, 1902, Pope Leo XIII appointed James Keane from the Archdiocese of St. Paul as the third bishop of Cheyenne.

[14] On January 19, 1912, Patrick McGovern from the Diocese of Omaha was appointed the fourth bishop of Cheyenne by Pope Pius X.

On August 2, 1947, Hubert Newell of the Archdiocese of Denver was appointed as coadjutor bishop of the Diocese of Cheyenne to assist McGovern by Pope Pius XII.

[17] On December 14, 1999, David L. Ricken was appointed as coadjutor bishop of the diocese by Pope John Paul II.

On October 19, 2009, Benedict XVI appointed Paul D. Etienne of the Archdiocese of Indianapolis as bishop of the Diocese of Cheyenne .

[24] In January 2004, Hart was named in a civil lawsuit alleging that he sexually abused three children while serving in Kansas City and Cheyenne.

[25] Reverend Anthony Jablonowski was convicted in April 2004 of taking indecent, immodest or immoral liberties with a minor during the early 1980s in Guernsey.

[26] In 2005, a fifth person alleged abuse by Hart in 1973 or 1974, when the man was a 12-year-old parishioner at St. John Francis Regis Parish.

[27] In 2010, Bishop Etienne requested an investigation by the Vatican into sexual abuse allegations by 11 men against Hart.

[37] However, the Congregation rebuked Hart;...for his flagrant lack of prudence as a priest and bishop for being alone with minors in his private residence and on various trips, which could have been potential occasions endangering the ‘obligation to observe continence’ and that would ‘give rise to scandal among the faithful,'[38]As of 2020, the Diocese of Cheyenne served 54,995 Catholics (8.6% of 578,759 total) on 262,333 km2 (101,287 sq mi) in 32 parishes.