Former Owner
- James Tanis1
- Jean Bondieu1
- Joachim Guerrinus de Montefegatesio1
- Johannes Cuno1
- Johannes, de Sancto Nabore1
- John Alfred Wigan1
- John Bellingham Inglis1
- John Couch Adams1
- John F. Fleming1
- John Gribbel1
- John Harrison-Broadley1
- John Henry Ellis1
- John Hindley1
- John Hope, 1st Marquess of Linlithgow1
- John Morgan1
- Joseph E. Widener1
- Juan de Aillon1
- Juan de Torquemada1
- Judith Lady Montefiore College1
- Julie Florence de Cossette1