The collection contains more than 15,000 letters and documents of the Van Ness-Philips family from the late 1700's to the early 1900's. The oldest part of the collection focuses on General John P. Van Ness, son of Peter Van Ness, a congressman from New York and later the mayor of Washington D.C. There is also much political correspondence between John P. Van Ness and Martin Van Buren, James Roosevelt and others concerning New York State affairs. Included in the series are some 30 signatures of autographic value, besides Van Buren and Roosevelt, among them: John Quincy Adams, Andrew Jackson, John Jacob Astor, Daniel Webster, Francis Scott Key, James Monroe, Nicholas Biddle, Albert Gallatin, Zebulon Pike, Benjamin Latrobe and Gilbert Stuart. Series I contains the Washington plat books, surveys and correspondence of his father-in-law, David Burnes.

Miltary documents, correspondence and diaries of Officer John Van Ness Philip (d. 1862) who served in both the Mexican and Civil Wars are of signicant importance concerning the Kossuth mission aboard the U.S.S. Mississippi in 1851 and the invasion of California in 1846 aboard the U.S.S. Cyane in the Mexican American War.

The collection also contains personal papers detailing the education of William Henry Philip at Lenox Academy and Williams College and his travels in Europe. There are also papers of military and political value regarding his service in the Civil War, candidacy for Congress, and life as a lawyer and businessman in Washington, D.C. Included in the collection are the personal papers and correspondence of his wife, Eliza Worthington Philip and their two sons, John Van Ness Philip and Herman Hoffman Philip, who were both active in business and politics.

The Philip Family Papers contains letters of Theodore Roosevelt, as well as letters of Franklin D. and Eleanor Roosevelt. Also included are writings, speeches, illustrations and volumes.

Material relating to the Worthington family, ca. 1817-1900, includes correspondence, 1817-21, between Midshipman Thomas B. Worthington and his physician father Charles Worthington; correspondence and papers of lawyer William M. Worthington; correspondence, ca. 1830's-1875, of John G. Worthington, covering his early law practice in Cincinnati, Ohio, and later years in Washington, D.C.; and family correspondence, ca. 1850's-1900.

Items of note also include one folder of oversize material containing commissions of Herman Hoffman Philip, that are signed by Presidents T. Roosevelt, Taft, Harding, Coolidge, Hover, F.D. Roosevelt. There are also some commissions of John Van Ness Philip (d. 1949) signed by President McKinley.