The papers of James Asheton Bayard (1767-1815) and his son, Richard Henry Bayard (1796-1868), senators, lawyers, and diplomats, span the years 1797-1885 and consist of diaries, correspondence, diplomatic documents, congressional material, legal and financial records, printed matter, newspapers, and newspaper clippings.

A major portion of the collection is comprised of the Correspondence series organized in two distinct groups. Set I covering the period 1797-1817 relates mainly to James A. Bayard, and concerns Federalist politics, repeal of the Judiciary Act of 1800, rechartering the first Bank of the United States, the War of 1812, and foreign affairs. James Asheton's correspondence for 1813-1815 concerns the peace negotiations that culminated in the Treaty of Ghent in 1814. Many of Bayard's letters were written to his cousin, Andrew Bayard (1762-1833), a merchant in Philadelphia, and to his wife's father, Richard Bassett (1745-1815), a "midnight judge" appointee of President John Adams. Other prominent correspondents include John Quincy Adams, R. G. Beasley, Erick Bollmann, Henry Clay, Albert Gallatin, James Madison, James Monroe, and Count Nikolai Romanzoff.

Set II of the Correspondence series covers the period 1834-1868 and consists chiefly of letters to and from Richard H. Bayard relating to Delaware politics, administration of the assets of the Bank of the United States, 1841-1845, the Delaware state militia, and diplomatic relations with Belgium. Correspondents include Henry Clay, John M. Clayton, William L. Marcy, John P. Montgomery, Simon Spearman, William Temple, and Daniel Webster.

Among the items in the Miscellany series are diplomatic documents, a key to the cipher used in some of the letters, and reports and other papers concerning the United States Navy, British Royal Navy, and the Delaware State Militia. The Printed Matter series includes the proceedings of the impeachment of William Blount,1797; speeches delivered in the United States House of Representatives and Senate by James A. Bayard, 1802-1812, and in the Senate by Richard H. Bayard, 1837-1841; documents concerning the presidential election in 1800; reports of the Committee on Naval Affairs of the United States Senate, 1842-1844; state and federal documents; presidential messages to Congress; Belgian documents; State Department circulars; directories of the 27th and 28th congresses; newspapers and newspaper clippings; genealogical material concerning the Bayard family; and other material.

Some of the correspondence and diplomatic documents are in French, German, and Russian. Whenever dual dating appeared, the material was arranged according to the Gregorian calendar rather than the Julian calendar which is later by twelve days.