Former Owner
- John F. Fleming1
- John Harrison-Broadley1
- John Harvey Treat1
- John Rolls, 1st Baron Llangattock1
- John Ruskin1
- John Shelton Lawrence1
- John Trotter Brockett1
- John William Harshberger1
- Joseph Barrois1
- 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