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.

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.

[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.

The opening of large tracts of land to settlement and the arrival of the railroad greatly increased the population of Idaho.

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.

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.

Beginning in the middle of the twentieth century, large numbers of migrant workers from Mexico arrived in 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.

[1] Pope John Paul II then named Tod Brown from the Diocese of Monterey-Fresno as the sixth bishop of Boise in 1989.

[15] The diocese operates five hospitals: In 1985, Mel Baltazar was sentenced to seven years in prison after being convicted of lewd conduct with a 15-year-old boy.

The presiding judge stated that the Catholic Church protected Baltazar while he abused children in previous positions with other dioceses.