Erected by Pope Paul VI on July 14, 1978, its jurisdiction extends over San Bernardino and Riverside counties.

[2] During the 18th century, the San Bernardino and Riverside areas were part of the province of Las Californias in the Spanish colony of New Spain.

[4] The first European settlement in present-day Riverside County was an estancia, or farmer, established by the Mission San Luis Rey de Francia at the Luiseño village of Temescal.

In 1819, Franciscan missionaries established the San Bernardino de Sena Estancia in what is today Redlands.

In 2001, Barnes inaugurated the Annual Bishop's Golf Classic to fund scholarships to families who are unable to afford a Catholic education for their children.

During his tenure, Barnes closed four primary schools in the California communities of Barstow, Banning, Apple Valley[11] and San Bernardino.

[15] In July 2003, a US Supreme Court ruling on a California law forced prosecutors to drop the O'Keefe case.

The diocese charged that the archdiocese gave them false information on Paul R. Shanley, a priest who transferred to San Bernardino from Boston in 1990.

Despite Shanley having a record of sexual abuse of minors in Massachusetts, the archdiocese described him to the diocese as "a priest in good standing".

[20] Reverend Joseph Jablonski, a visiting priest with the Missionaries of the Sacred Heart, was removed from ministry in the diocese in 2014.

Jablonski worked in three Illinois dioceses until 2018, when his name appeared on the San Bernardino list of credibly accused priests.

[21] Reverend Marcelo De Jesumaria of Arrowhead was convicted in May 2015 of sexually abusing a female passenger during an August 2014 flight from Philadelphia to Los Angeles.

[25] Nick Flores in December 2019 sued the diocese, claimed that he had been sexually abused by Reverend Louis Perreault at Our Lady of the Valley Church in Hemet in the 1990s.

[27] Alberto Rojas (2019–2020)[30] Our Lady of the Desert School in Yucca Valley is not associated with the diocese, though it offers traditional Catholic education.