Former Owner
- John Trotter Brockett1
- John William Harshberger1
- Joseph François René de Kergariou1
- Joseph Jekyll1
- Joseph Pope1
- Joseph Whitney1
- Joseph-Félix Allard1
- Juana I of Castile1
- Julie Florence de Cossette1
- Julius Hess1
- Justin MacCarthy Reagh1
- K. B. Starkie1
- Klaus Dieter Dahmen1
- Kloster Kuringen1
- Kulturhistorisches Museum Magdeburg1
- Latham family1
- Laurence Kirby1
- Laurentius van der Torqel1
- Long Island Historical Society, Maine1
- Louis H. Silver1