It includes the city/county of Denver and the following counties: Adams, Arapahoe, Boulder, Broomfield, Jefferson, Larimer, Logan, and Weld.

[3] In 1878, Frank Michaud funded the purchase of a wooden building in Fort Collins to become St. Joseph's, the first Catholic church in that city.

During his 28-year-long tenure, Matz made Catholic education his top priority, establishing dozens of parochial schools.

[6] However, Matz met opposition from many priests and his ambitious building projects drove the diocese into a large amount of debt.

[10] Tihen was forced to defend the church in Colorado from the Ku Klux Klan, which he condemned as "an anti-Catholic and un-American society.

[12] Vehr cooperated with the New Deal programs of President Franklin D. Roosevelt, asking priests to celebrate mass at the two dozen Civilian Conservation Corps camps established in Colorado.

[13] In 1965, Vehr launched the Archdiocesan Development Program to accommodate Colorado's Catholic population, which had tripled in size since his arrival in 1931.

[13] He also erected 43 new parishes and expanded St. Thomas Seminary, which reached its peak enrollment of 274 seminarians during Vehr's tenure.

[13] When Vehr retired in 1967, Pope Paul VI appointed Bishop James Casey of Lincoln as the second archbishop of Denver.

He joined the Colorado Council of Churches, and allowed Catholics to participate in the crusades of the evangelist Billy Graham.

To replace Stafford, John Paul II selected Bishop Charles J. Chaput from the Diocese of Rapid City as the next archbishop of Denver.

In 2012, Pope Benedict XVI named Bishop Samuel Aquila of the Diocese of Fargo as the fifth and current archbishop of Denver.

[22] Tim Evans, pastor at St. Elizabeth Ann Seton Parish in Fort Collins, was convicted of sexual assault in 2007.

[23] In January 2023, Scott Venti sued the archdiocese, claiming that he had been sexually abuse multiple times during the 1990s by Evans in Fort Collins.

[25] In late 2019, a man reported to authorities that he had been sexually molested multiple times by James Moreno between 1978 and 1980 at various church locations within the archdiocese.

It named an additional nine clergy with credible accusations of sexual abuse and 46 alleged victims in both in the archdiocese and the Diocese of Pueblo.

[28][29] A total 52 priests who served in the Colorado diocese were named in the final report as having committed acts of sex abuse.

[30] Among other priests, the report had comments about these individuals: In August 2022, a woman sued the archdiocese, claiming sexual abuse by Marshall Gourley from age seven to 11 at the Our Lady of Guadalupe Church during the early 1980s.

In 1910, a group of priests and laymen formed the Catholic Publishing Society, which took over management of the Register, made it the diocese's official newspaper.

[36] In 1913, Hugh McMenamin, the rector at the Cathedral of the Immaculate Conception, bought a controlling stake in the Catholic Publishing Society and named Matthew J. Smith as its editor.