Correspondence, journals, notebooks, official records, printed matter, photographs, and other papers relating to Colhoun's service with the U.S. Navy's Mediterranean Squadron and Brazil Squadron (also known as South Atlantic Squadron) prior to the Civil War, his Civil War service with blockade squadrons, and his service as commander of the USS Hartford (Sloop of war), flagship of the Asiatic Squadron. Subjects include American diplomacy and naval strength in East Asia. Includes records of the USS Albany (Sloop of war), USS Congress (Frigate), USS Ladona (Steamer), USS St. Lawrence (Frigate), and USS Saugus (Monitor).