1700 to 1860

The first Catholics to arrive in present day Boise were French-Canadian fur trappers in the mid 1700's. After the Louisiana Purchase in 1803, when the area became part of the United States, it fell under the jurisdiction of the Diocese of Baltimore in Maryland.

In 1815, 19 Iroquois (Haudenosaunee) migrated into Idaho from eastern Canada. Having had contact with Catholic missionaries in Canada, the Iroquois spoke to the Native American tribes about heaven and how they needed the "black robes" to show them how to get there.

Over the next 25 years, the Nez Perce and Flathead tribes sent four delegations to St. Louis, Missouri to speak with Catholic officials, attempting to recruit a priest for their communities. In 1840, the Diocese of St. Louis sent Pierre-Jean De Smet, a Jesuit priest, to minister to the tribes. De Smet celebrated the mass in Idaho in July 1840 at Henry's Lake.^[1]

Nicholas Point in 1843 constructed the Cataldo Mission along the St. Joe River near present-day St. Maries. It was the first mission church in Idaho. The Cataldo Mission later moved to its present location on the Coeur d'Alene River. It is the oldest building in Idaho.^[1][2] With the establishment by the Vatican in 1846 of the Vicariate Apostolic of Oregon Territory, all of the Idaho area was under this jurisdiction.^[3] For the next 19 years, most of the Catholics in Idaho belonged to the Native American tribes.

1860 to 1900

With the discovery of gold in the Boise Basin in 1862, tens of thousands of miners flooded the area, including large numbers of Irish Catholics.^[4] Due to the area's growth, President Abraham Lincoln created the Territory of Idaho in 1863. That same year, the first church for the European Catholics, St. Joseph's, was built in the booming mining town of Idaho City.^[5]

Pope Pius IX in 1868 erected the Vicariate Apostolic of Idaho and Montana, covering a vast area west of the Northern Rockies. At that time, both the territory and the apostolic vicariate included the current state of Idaho and the western portions of Montana and Wyoming.^[1][6] The pope named Louis Lootens of the Archdiocese of San Francisco as the first vicar apostolic. When the vicariate was established, the population of Idaho was approximately 20,000, of whom only 1,500 were Catholic.

By the 1870s, the Idaho gold rush had ended, miners were leaving the territory and its towns were drying up. When Lootens' health began to fail, the Vatican allowed him to resign from the vicariate in 1876.^[1] The vicariate would be without a bishop for the next eight years.

In 1887, Pope Leo XIII appointed Alphonse Glorieux as the second vicar apostolic of Idaho and Montana. Glorieux designated Boise as his see city.

On August 23, 1893, Leo XIII erected the Diocese of Boise, covering the entire state of Idaho. He appointed Glorieux as its first bishop. At that time, there were approximately 7,000 registered Catholics in the state. In 1894, the Sisters of the Holy Cross opened St. Alphonsus Hospital, the first hospital in Boise.^[7]

1900 to 1950

In 1906, Gladieux laid the cornerstone for the Cathedral of St. John the Evangelist in Boise. The opening of large tracts of land to settlement and the arrival of the railroad greatly increased the population of Idaho. The diocese grew dramatically over the following century. One group of significance are the Basque people, who began immigrating to Idaho early in the twentieth century and primarily worked within the sheep industry. (Approximately 15,000 of their descendants remain in the diocese today.)^[1] Glorieux died in 1917.

Succeeding Glorieux as bishop in 1918 was Daniel Gorman from the Archdiocese of Dubuque, selected by Pope Benedict XV. Gorman oversaw large growth within the diocese during his nine years as bishop, adding 32 diocesan priests, completing construction on the cathedral, and doubling enrollment in parish schools.^[8]

After Gorman died in 1927, Pope Pius XI named Edward Kelly from the Diocese of Baker City as his replacement.^[9] Kelly served for 28 years until his death in 1956.^[10] The next bishop of Boise was Auxiliary Bishop James J. Byrne from the Archdiocese of St. Paul, selected by Pius XII in 1956.

1950 to 2000

Beginning in the middle of the twentieth century, large numbers of migrant workers from Mexico arrived in the diocese. Some settled permanently in the region, while many others remained migratory and would return to Mexico after the harvest. Toward the latter part of the century, the number of immigrants from Mexico and other parts of Latin America increased dramatically, with the vast majority of them settling permanently in the southern part of the diocese. So many immigrants have now made Idaho their home that people of Latin American heritage now constitute well over half of the Catholics within the diocese.^{[citation needed]}

Byrne became archbishop of Dubuque in 1962.^[1] The fifth bishop of Boise, Sylvester W. Treinen from the Diocese of Bismarck, was chosen in 1962 by Pope John XXIII. As bishop, he is remembered for implementing the reforms of the Second Vatican Council. He retired in 1988.^[1] Pope John Paul II then named Tod Brown from the Diocese of Monterey-Fresno as the sixth bishop of Boise in 1989. He became bishop of the Diocese of Orange in 1998.^[11]

In 1999, Auxiliary Bishop Michael P. Driscoll of Orange was appointed bishop in Boise by John Paul II.^[12]

2000 to present

After Driscoll retired In 2014, Pope Francis appointed Bishop Peter F. Christensen of the Diocese of Superior as the eighth bishop of Boise.^[13] In April 2020, Christensen issued a memo containing orders for diocese priests, including an order banning them from celebrating mass ad orientem (facing the altar).^[14] As of 2023, Christensen is the current bishop of Boise.

Sexual abuse

In 1985, Mel Baltazar was sentenced to seven years in prison after being convicted of lewd conduct with a 15 year old boy. Baltazar met the victim when he was serving as a chaplain at St. Alphonsus Medical Center. The presiding judge stated that the Catholic Church protected Baltazar while he abused children in previous positions with other dioceses.^[16] In 2003, a San Diego man sued the Diocese of Boise and several other dioceses, claiming that Baltazar sexually abused him in California and other locations for five years during the 1970s.^[17]

Deacon Robert Howell was arrested in November 2004 on charges of possessing child pornography. He pleaded guilty and was sentenced in March 2005 to 18 months in prison.^[18] Some of Howell's former parishioners were angry with the diocese for waiting until March to inform them about Howell.^[19]

In September 2018, W. Thomas Faucher pleaded guilty to possession of child pornography, distribution of child pornography, and possession of marijuana.^[20] Chatroom conversations obtained by law enforcement revealed Faucher's intent to use marijuana to drug children and operate a child pornography ring that also involved the rapes of these children.^[21] Faucher had satanic interests and admitted to acts of blasphemy and desecration.^[22] That same year, two individuals reported to the diocese that they had been sexually abused as minors by Faucher. In December 2018, Faucher was sentenced to 25 years in prison.^[22] The diocese evicted Faucher from his house while he was in jail, and performed an exorcism on the property before putting it up for sale.^[23][24] In 2020, Faucher died in prison.^[25][26]

The diocese in October 2019 released a list of 15 priests and one deacon with credible accusations of sexual abuse of children.^[27]

Apostolic Vicars of Idaho

1. Louis Aloysius Lootens (1868–1876), appointed Auxiliary Bishop of Vancouver Island
2. Alphonse Joseph Glorieux (1885–1893), appointed Bishop of Boise upon erection of diocese

Bishops of Boise

1. Alphonse Joseph Glorieux (1893–1917)
2. Daniel Mary Gorman (1918–1927)
3. Edward James Kelly (1927–1956)
4. James Joseph Byrne (1956–1962), appointed Archbishop of Dubuque
5. Sylvester William Treinen (1962–1988)
6. Tod David Brown (1988–1998), appointed Bishop of Orange
7. Michael Patrick Driscoll (1999–2014)
8. Peter F. Christensen (2014–present)

Other priest of this diocese who became a bishop

William Keith Weigand, appointed Bishop of Salt Lake City in 1980 and later Bishop of Sacramento