Mount Saint Mary's University was founded by the Sisters of St. Joseph of Carondelet in 1925 as the first Catholic women's college west of the Mississippi. It comprises two historic sites, the Chalon Campus high above Brentwood (1930), and the Doheny Campus, which occupies the former estate of Edward and Estelle Doheny, including the Doheny Mansion at 8 Chester Place (1899).

Collections include pamphlets and ephemera documenting the growth, industries, transportation, and social organizations of Los Angeles and greater southern California; photograph collections; thousands of books related to southern California; and numerous archival collections related to indiviuals, the citrus industry, and businesses in the Inland Empire.