The Dias Photographic Collection contains more than 30,000 prints, slides, and negatives of photographs taken by professional photographer Manuel Dias. Dias worked for the Modesto Bee and the Stanislaus County Office of Education as an aerial photographer, and maintained his own private photography business in Modesto, California. The aerial photography component includes photographs that depict the agriculture, industry, irrigation, recreation, roadways, schools, and urban areas of the San Joaquin Valley.  The Portuguese culture component includes photographs that depict Portuguese culture in the Azores, Portugal, Madeira, California, and Hawaii, with a focus on farming, seafaring, bullfighting, and portraiture.