Guillaume de Cahaignes, a French knight who participated in the Norman conquest of England, and lord of what is now Cahagnes, was given Milton in Buckinghamshire and the Sussex village of Horstede (The Place of Horses in Old English).
The latter became Horstede de Cahaignes and in time Horsted Keynes.
The place name is first attested in the Domesday Book of 1086.
The village has been formally twinned with the Normandy village of Cahagnes since 1971.
The Horsted Cahagnes Society promotes social and cultural links, and organises annual exchange visits between the two places.

On Saturday, 28 August 1624, Horsted Keynes hosted what is believed to be the earliest known organised cricket match in Sussex.
Knowledge of it stems from the death thirteen days later of Jasper Vinall, on whom an inquest was held.
He had suffered a head injury during the game when accidentally hit by a cricket bat.

Two months before being assassinated, U.S. President John F. Kennedy slept in the parish when he stayed one Saturday night at Birch Grove, the home of the former Prime Minister, Harold Macmillan.
The American Secret Service closed the village that night, siting their communication hub in the Lounge Bar of The Crown Inn.

 
On 1 July 2003 a lightning bolt struck the electricity pole beside The Crown public house on the village green which has stood there for at least 300 years and probably much longer.
The roof and much of the building were destroyed in one of the largest fires in the area for many years.
The fire did not spread to the petrol storage tanks of the adjacent Crown Garage.
In May 2007 a telephone pole was struck, removing communications from much of the village.
Several homes in Lewes Road were left without a telephone service for over one month whilst permission was sought to dig on private land to relay a cable.

This part of Sussex was known for its iron industry long before the industrial revolution and the coming of the railways.
Little remains of this now, except for the hammer ponds and other traces of this activity dotted around the surrounding countryside, although iron working is remembered in many local place names.
Guillaume de Cahaignes, a French knight who participated in the Norman conquest of England, and lord of what is now Cahagnes, was given Milton in Buckinghamshire and the Sussex village of Horstede (The Place of Horses in Old English). The latter became Horstede de Cahaignes and in time Horsted Keynes. The place name is first attested in the Domesday Book of 1086. The village has been formally twinned with the Normandy village of Cahagnes since 1971. The Horsted Cahagnes Society promotes social and cultural links, and organises annual exchange visits between the two places.
On Saturday, 28 August 1624, Horsted Keynes hosted what is believed to be the earliest known organised cricket match in Sussex. Knowledge of it stems from the death thirteen days later of Jasper Vinall, on whom an inquest was held. He had suffered a head injury during the game when accidentally hit by a cricket bat.
Two months before being assassinated, U.S. President John F. Kennedy slept in the parish when he stayed one Saturday night at Birch Grove, the home of the former Prime Minister, Harold Macmillan. The American Secret Service closed the village that night, siting their communication hub in the Lounge Bar of The Crown Inn.
 
On 1 July 2003 a lightning bolt struck the electricity pole beside The Crown public house on the village green which has stood there for at least 300 years and probably much longer. The roof and much of the building were destroyed in one of the largest fires in the area for many years. The fire did not spread to the petrol storage tanks of the adjacent Crown Garage. In May 2007 a telephone pole was struck, removing communications from much of the village. Several homes in Lewes Road were left without a telephone service for over one month whilst permission was sought to dig on private land to relay a cable.
This part of Sussex was known for its iron industry long before the industrial revolution and the coming of the railways. Little remains of this now, except for the hammer ponds and other traces of this activity dotted around the surrounding countryside, although iron working is remembered in many local place names.
Horsted Keynes