Former Owner
- John Couch Adams1
- John Edgar Ker1
- John Hope, 1st Marquess of Linlithgow1
- John Roland Abbey1
- John Shelton Lawrence1
- John Thomas Beer1
- Joseph Barrois1
- Joseph Pope1
- Juan Antonio de la Reguera1
- Juan de Aillon1
- Juan de Torquemada1
- Julie Florence de Cossette1
- Julius de Cardelinis1
- Katherine Somerset Wyttenbach Fenwick1
- L. Paganthus1
- Lajos Graf Apponyi de Nagy-Appony1
- Lambach Abbey1
- Lancino Curti1
- Laurence William Hodson1
- Leo Olschki1