- Lea, Pryor, 1794-18791
- Lee, Charles A. (Charles Alfred), 1801-18722
- Lee, James, 1818-18661
- Lee, Samuel H. P. (Samuel Holden Parsons), 1772-18631
- Lee, William, 1778-18632
- Leeds, G. J.1
- Lehmann, Karl Gotthelf, 1812-18634
- Leidy, Joseph, 1823-18914
- Leigh, Edwin.2
- Leigh, John, 1813-18871
- Letcher, S. M.1
- Leubuscher, Rud. (Rudolph), 1821-18611
- Lieber, Francis, 1800-18721
- Liebig, Justus, Freiherr von, 1803-18732
- Lillie, James.1
- Lindsay & Blakiston.2
- Lindsley, John Berrien, 1822-18972
- Lindsly, Harvey, 1804-18891
- Linton, M. L. (Moses L.) 1808-18721
- Linton, M. L. (Moses L.), 1808-18722