Duffield Frith was, in medieval times, an area of Derbyshire in England, part of that bestowed upon Henry de Ferrers (or Ferrars) by King William, controlled from his seat at Duffield Castle. From 1266 it became part of the Duchy of Lancaster and from 1285 it was a Royal Forest with its own Forest Courts.
It extended from Duffield to Wirksworth and from Hulland to Heage. Most of it became the ancient parish of Duffield, which contained the townships of Hazlewood, Holbrook, Makeney and Milford, Shottle, and Windley, and the chapelries of Belper, Heage and Turnditch. The chapelry of Belper – or "Beaureper" – was built by the Duke of Lancaster for the use of the foresters.
The area had been noted for centuries for the quantity of deer, mostly fallow, but there was also wild boar. There were also wolves, at least until the end of the thirteenth century.