Helm's Deep is the mighty fortress of Rohan. It is named for Helm Hammerhand, the hero of ancient wars who made his refuge there. It lies in a forge that winds its way below three-peaked Thrihyrne in the nothern White Mountains. It has long been the defence centre of the Westfold and the Kings of Rohan have over the ages constructed a cast and seemingly impregnable system of fortification in the gorge.

The entrance to the Deep is just a tall wooden gate that is nowe rotting away with age. Apon a great spur of rock lies the Hornburg. This is a massive walled keep. It is said that the Hornburg was built by the hands of giants in the days of the sea-kings of Gondor. From the keep to the mouth of Helm's Gate runs the Deeping Wall. This is a great fortified wall. Wide enough to enable four men at onve to stand ontop of it. This wall is incredibly strong and thick.

Beneath Helm's Deep lie the Glittering Caves of Aglarond, a spectacular cavern system which is truly one of Middle-earth's natural wonders and has probed in times past to be a sage haben when the Kingdom of Rohan is under attack.

It was once said that the Deeping Wall was unpenatrable. There is one weakness in this thick wall. A small culvert at it's base. Saruman made explosives to be placed there. He breached the wall and his army of Uruk-hai swarmed in. It would have been a victory for Saruman if it wasn't for Gandalf and the Rohorrim.