This cool secluded garden, moated by the River Darent, is a peaceful haven after the noise and bustle of Dartford.
The curious name derives from the Commandery of the Knights Hospitallers of the Order of Saint John of Jerusalem.
This military order, whose headquarters was in Jerusalem, was given the manor in 1199, probably as pious contribution to the Crusades.
The original Commandery of the Knights was dissolved at the Reformation. Only the chapel with its buttressed flint walls and three tall lancet windows survives.
St John's is approached down a short drive from the village of Sutton-at-Hone.
The house is first seen across the waters of the moat and between a magnificent Cedar of Lebanon and a copper beech.
The pleasant two-storey stuccoed house has a steeply pitched roof with dormer windows. It was the creation of Abraham Hill, one of the founders of the Royal Society.
He acquired St John's in 1665 and lived there until his death in 1721. The vast cedar was probably planted by Hill in the late 17th century when the house was built. He also introduced a cider industry from Devon.
A recently established orchard recalls Hill's innovation but no traces remain of the original cider apples and perry pears he planted here.
Between 1755 and 1776 St John's was the home of Edward Hasted, the eminent historian of Kent. His additions include the south door, rich plasterwork in the house and the sash windows. Much of the decoration in the house is as Hasted left it including the rococo chimneypiece in Mrs Hasted's boudoir. The expense of these improvements contributed to Edward Hasted's financial ruin.
From the house undulating lawns, planted with a broad avenue of chestnuts, stretch away to the limes and willows edging the moat.
There are a number of splendid specimen trees here including a descendant of one of the willows on St Helena under which Napoleon was buried. Spring and summer flower borders are bright with bulbs and herbaceous plants.
St John's Jerusalem is now in the care of the National Trust.
However, the Knights live on in the name of this delightful property. Only the chapel and the garden are open to the public.