The research library of the Historical Society contains an important collection of original manuscripts and printed ephemera. Manuscripts include personal and business account books, minute books, diaries, letters, deeds, land patents and original writings. Local newspapers in the Leland Jordan Collection and others comprise the bulk of the printed materials. Few county historical societies in Maryland have comparable collections. There are also numerous examples of rare books, family Bibles, maps, broadsides, handbills, booklets, programs, certificates, diplomas, rosters and directories.