Depending on your area of research, there are many databases that the Library subscribes to that may be of interest. Many of them are archives of newspapers and their advertisements from around the country can be helpful in finding information of a more regional nature.
The subscription resources marked with a padlock are available to researchers on-site at the Library of Congress. If you are unable to visit the Library, you may be able to access these resources through your local public or academic library.
C19 Index draws on the strength of established indexes such as the Nineteenth Century Short Title Catalogue (NSTC), The Wellesley Index, Poole's Index, Periodicals Index Online and the Cumulative Index to Niles' Register 18111849 to create integrated bibliographic coverage of over 1.7 million books and official publications, 70,000 archival collections and 20.9 million articles published in over 2,500 journals, magazines and newspapers. C19 Index now provides integrated access to 13 bibliographic indexes, including more than three million records from British Periodicals Collections I and II, together with the expanded online edition of the Dictionary of Nineteenth-Century Journalism (DNCJ).