- Peck, George B. Jr. (George Bacheler), 1843-1934, author1
- Pennsylvania. Hospital Department1
- Perkins, Stephen H. (Stephen Higginson), 1804-18771
- Potter, William W. (William Warren), 1837-1911, author1
- Quint, Alonzo H. (Alonzo Hall), 1828-18961
- Reed, William Howell, 1837-1914, author1
- Robertson, Charles A. (Charles Archibald), 1829-18801
- Safford, E. D.1
- Sanderson, James M., author1
- Sartain, John, 1808-1897, engraver1
- Satterlee, R. S. (Richard Sherwood), 1798-1880, author1
- Snow, Edwin M. (Edwin Miller), 1820-18881
- Souder, Edmund A., Mrs1
- Southern Hospital Association for Disabled Soldiers. Committee on Correspondence.1
- Steiner, Lewis H. (Lewis Henry), 1827-18921
- Swinburne, John, 1820-18891
- Ulke, Henry, 1821-1910, photographer1
- United States Sanitary Commission.55
- United States Sanitary Commission. Cincinnati Branch.4
- United States Sanitary Commission. Cleveland Branch.1