Collection includes materials related southern California tourism, the Mission Revival movement, peace movement (1st half 20th century, citrus industry, and materials related to specific collections,including fine art, statuary, bells, crosses, dolls, aviation, Native American basketry, and Asian arts.

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).

Founded in 1956, the Orange Empire Railway Museum preserves the railway history of Los Angeles and Southern California. In addition to its large collection of full size railway cars and locomotives, its archives contains extensive materials on the Los Angeles Railway and Pacific Electric Railway, as well as the mainline railroads that served Southern California.