Former Owner
- John C. Jackson1
- John Fenn1
- John Henry Nash1
- John Roland Abbey1
- John Ruskin1
- John Shelton Lawrence1
- John Thomas Beer1
- Joseph Halle Schaffner1
- Joseph Pope1
- Juan Burgueño1
- Juan Rodriguez1
- Juan de Gayferos de Eguiraum1
- Juana I of Castile1
- Julian Burgueño1
- Justin MacCarthy Reagh1
- Jérôme Pichon1
- Jón Þorstensson1
- Katherine Somerset Wyttenbach Fenwick1
- Konrad von Maurer1
- Lady Frances Bentinck1