Former Owner
- Joseph François René de Kergariou1
- Joseph Jekyll1
- Joseph Marie Sormani1
- Joseph Whitney1
- Josephine Widener Wichfield1
- Julie de Busnel1
- Justin MacCarthy Reagh1
- Lady Margaret Ayloffe1
- Lambertus Eerens1
- Latham family1
- Lathrop C. Harper, Inc.1
- Lathrop Colgate Harper1
- Laurence Kirby1
- Laurent Campagne1
- Legoué1
- Leo Olschki1
- Librairie Damascène Morgand1
- Libri, Edoardo, active 20th century1
- Lisa Norris Elkins1
- Long Island Historical Society, Maine1