Don't know where to start? Try one of the following database portals. They allow researchers to search across multiple databases produced by the same publisher.
America's Historical Newspapers Large online collection of historic American newspapers. Part of the Archive of Americana, a collection of various newspaper databases, by Readex.
African American Newspapers Online collection of the most extensive African American newspaper archives in the United States—those of the Wisconsin Historical Society, Kansas State Historical Society and the Library of Congress. Also part of the Archive of Americana by Readex.
Accessible Archives Digital collections of important 19th century African American and Civil War newspapers.
Chronicling America Website providing access to information about historic newspapers and select digitized newspaper pages.
America's Historical Imprints Digital collection of early American imprints, broadsides and ephemera. Based on the American Antiquarian Society's collections.
Harper's Weekly, 1857-1912 Contains scanned images of all of the pages of Harper's Weekly together with a series of indexes.
Opinion Archives Digital collection of current issues and backfiles of a number of leading U.S. opinion publications including the New Yorker (1925-present), the Nation (1865-present), Commentary (1945-present), the American Spectator (1967-present), the National Review (1955-present), New Republic (1914-present), Commonweal (1924-present), the New York Review of Books (1965-present), and Harper's (1850-present).
Digital Manuscript Collections, Oral Histories, etc.
History Vault: Collection of digitized microfilm. See especially: The Records of Southern Antebellum Plantations
Everyday Life & Women in America, 1800-1920 Full text of momographs, periodicals, pamphlets and broadsides from Duke university's Sallie Bingham Center for Women's History and Culture, and the New York Public Library.
Making of the Modern World Digitized library of economic and business literature on topics like the Industrial Revolution, the development of modern capitalism, and the emergence of modern economics.
Jewish Life in America Original manuscript collections from the unique holdings of the American Jewish Historical Society in New York.
Slavery, Abolition and Social Justice, 1490-2007 Brings together documents and collections covering the period 1490-2007 from libraries and archives across the Atlantic world, including the United States.
History Makers Database of video oral history of African American business, medical, and law leaders.
Oral History Online An index to English-language oral histories from around the world, Oral History Online provides links or location information for oral histories available on the Web or held by repositories and archives around the world.