Stretching as it did over practically the whole length of the present-day county it was much larger than the other two.
Bordering on Sherwood Forest, it made a continuous area stretching from the River Derwent to the Trent.
The custodians were the Cauz family of Laxton in Nottinghamshire, who had inherited it from Geoffrey Alselin who was related by marriage to Gerard de Normanville, who it is believed had been made custodian of Sherwood Forest by William I. Matilda de Cauz had married Ralph fitzStephen, chamberlain to Henry II.
It may be about this time that William de Ferrers II extended Duffield Frith to the east of the River Derwent to build a new hunting lodge at Belper.
Volume 2: Medieval Derbyshire, Cardiff: Merton Priory Press