| May 30, 1886 | First Mass at St. Mary Church, Eugene |
| March 25, 1887 | Sisters of St. Mary of Oregon, Beaverton, founded |
| May 8, 1888 | St. Monica, Coos Bay (formerly Marshfield), founded by Fr. Peter Beutgen |
| June 16, 1889 | St. Mary's Home for Boys, Beaverton, cornerstone laid |
| July 29, 1893 | St. Mary's Academy & College, Portland, received State Charter. First liberal arts college for women in Pacific N.W. |
| January 28, 1894 | Holy Rosary Church, Portland, dedicated as Dominican Mission |
| October 11, 1896 | St. Anne Church, Grants Pass, blessed. Mass offered for the first time |
| February 12, 1899 | Archbishop Alexander Christie appointed fourth Archbishop of Oregon City |
| September 2, 1901 | University of Portland blessed and dedicated by Archbishop Christie as "Columbia University" |
| November 9, 1922 | Catholic Truth Society of Oregon established by Archbishop Christie |
| June 1, 1925 | U.S. Supreme Court decision on the Oregon School Bill |
| February 19, 1926 | Archbishop Edward D. Howard appointed the fifth Archbishop of Oregon City |
| September 26, 1928 | Papal Decree changes the name of the Archdiocese of Oregon City to Archdiocese of Portland in Oregon |
| September 12, 1933 | Catholic Charities established |
| May 9, 1939 | Dedication of Central Catholic High School |
| March 1, 1955 | Trappist Abbey of Our Lady of Guadalupe, Lafayette, founded |
| December 9, 1966 | Archbishop Robert J. Dwyer appointed sixth Archbishop of Portland in Oregon |
| August 13, 1971 | Vicariate for Spanish-speaking established by Archbishop Dwyer |
| January 22, 1974 | Archbishop Cornelius M. Power appointed seventh Archbishop of Portland in Oregon |
| December 6, 1977 | Fr. Kenneth D. Steiner and Fr. Paul E. Waldschmidt, CSC, appointed Auxiliary Bishops of Portland in Oregon |
| January 29, 1981 | Southeast Asian Vicariate established by Archbishop Power |
| July 1, 1986 | Archbishop William J. Levada appointed eighth Archbishop of Portland in Oregon |
| April 30, 1996 | Archbishop Francis E. George, OMI, appointed ninth Archbishop of Portland in Oregon |
| July 24, 1996 | 150th Anniversary of the Archdiocese of Portland in Oregon |
| October 28, 1997 | Archbishop John G. Vlazny appointed tenth Archbishop of Portland in Oregon |
| December 24, 1999 | Archbishop Vlazny opens Holy Year Door at St. Mary's Cathedral of the Immaculate Conception to begin the Jubilee Holy Year 2000 |
| June 25, 2000 | Eucharist 2000, Feast of Corpus Christi, Archdiocesan celebration of the Jubilee Year 2000 |
| July 6, 2004 | Archdiocese of Portland in Oregon becomes the first diocese in the U.S. to declare Chapter 11 Bankruptcy |
| September 28, 2007 | Archdiocese of Portland in Oregon emerges out of Chapter 11 Bankruptcy |