- Aaron Snavely Poem, 18631
- Abel Smith Jr. Letter, 18631
- Abner B. Palmer Letter, 18641
- Abraham Lincoln1
- Abraham Lincoln Tintype,, 18641
- Abraham Lincoln, 19221
- Abraham Lincoln, Bust1
- Abraham Lincoln, Miniature Statue1
- Abraham and Tad Lincoln Albumen Print,, 18641
- Adelaide Colcock Papers, 1863/18701
- Adin B. Underwood Papers,, 1861/19264
- Admiral Porter's Fleet Running the Rebel Blockade of the Mississippi at Vicksburg, April 16, 1863, 18631
- Aileen B. Cowardin Friendship Book,, 1863/18701
- Albert N. Hubbard Letter, 18641
- Albert O. Stratton Journal, 18651