Bisley Detached is the name given to an area of the parish (of approximately 52 acres) which followed a separate line of descent from the rest of the parish after Henry de Leybourne, Lord of the Manor at the time, sold it to Hugh de Smershull in 1298.

Peter de Gaveston or Piers Gaveston, a favourite of King Edward II was granted the Manor of Bisley, but when he was killed, the King instructed a steward to seize his lands on behalf of the crown. The area which was sold by Henry de Leybourne had by this time descended to John de Arderne and was also seized, mistakenly. On petition to Parliament and Edward III (Edward II had abdicated in 1327), John de Arderne's land was restored to him. In the intervening period however, the parish boundary of Bisley had receded leaving John's land isolated from the rest of the parish by some 300 yards.

Bisley Detached is roughly triangular and now comprises just under 43 acres; it is bounded by Chobham parish on north side and Horsell parish on the other two sides.