Correspondence, telegrams, reports, memoranda, articles, autobiographical, biographical and genealogical material, financial and legal papers, annotated printed matter, scrapbooks, maps, photographs, and other papers relating chiefly to Porter's court-martial and cashiering out of military service on January 21, 1863, as a result of his conduct during the Second Battle of Bull Run on August 29, 1862, the review by a board of officers, his reinstatement, honorable retirement in 1879, congressional action taken, and presidential pardon. Documents support of fellow officers in Porter's charges of incompetence and slander against Generals John Pope and Irwin McDowell.

Also includes material concerning the conduct of the 5th Army Corps under Porter's leadership in the Peninsular Campaign, at Malvern Hill, Second Manassas, and Antietam; autobiographical and biographical studies relating to Porter's early military career, particularly in the war with Mexico and the Utah Expedition (1857-1860); correspondence and military papers dealing with Porter's Texas Expedition (1861) and the first Shenandoah Valley Campaign under Robert Patterson; unpublished biographical works by Theodore Akerly Lord covering Porter's military career from the Mexican War to the Shenandoah Campaign as well as by Carswell McClellan concerning the court-martial; and an ms. translation from the German pertaining to Ferdinand Franz Mangold's campaign in Northern Virginia in August 1862.

Correspondents include John C. Bullitt, Ulysses S. Grant, George Frisbie Hoar, Reverdy Johnson, George Brinton McClellan, George D. Ruggles, William Joyce Sewell, and Stephen Minot Weld.