The O'Neill Museum is located in the Los Ramos Street Historical district, where many of the first buildings were created in 1880s for the new town San Juan Capistrano. In 1976, the Cornwell Family, then the owners of the building and the nearby El Adobe restaurant donated the structure to the San Juan Capistrano Historical Society. The building became known as the O'Neill Museum after the O'Neill family donated a large sum of money to the society for the refurbishment of the structure. It now holds the archives of photos, books, documents, maps, genealogical records and oral histories for the historical society. Visitors today are allowed to view the house, which is furnished in the style of that period, and view all of the collected photos and archives of the town.