The Forest of Dean lies between the Severn and the Wye; it was, and perhaps still is, a country on its own between England and Wales. Its legal boundaries have changed many times but in fact are based upon the Hundred of St Briavels. The word forest has now come to mean a large tract of tres but its original meaning was "A certain territorie of woody ground and fruitful pastures, privileged for wild beasts and foules of the forest, chase and warren to rest and abide there in the save protection of the King, for his princely delight and pleasure".

In 1282 the Forest occupied all that triangle of ground between the Severn and the Wye. Its limits ran from Gloucester bridge, down to the Severn to the place where the Wye fell into the Severn, then up the Wye almost to Ross, across to Newent and back to Gloucester bridge.

For a time the power of kings was able to override and outweigh geographical considerations, but soon the area of the Forest began to shrink as the agricultural lands to the north and in the Severn vale were freed from its laws, having no great affinity with the rougher land within and around the Hundred of St Briavels.

By 1787, these boundaries were regarded as practically settled as shown on the maps of the Drivers, and in the autumn of 1833 the Dean Forest Commissioners decided to fix them using these maps as their guides. They started their perambulations at Littledean on a Tuesday and ended the day at Bream; they reached the Hoarthorns on Wednesday, Drybrook by Thursday, the Stenders on Friday, and on Saturday returned to Littledean. Thus the official area of the Forest of Dean became approximately 23,000 acres, but excluded much which, is to our eyes, so obviously and historically Forest - omitting even St Briavels itself, which was once the administrative centre of the Forest.