The ruins of the Große Harzburg are located above the spa town and the Radau valley, on the top of the Großer Burgberg hill at a height of 482.80 metres (1,584.0 ft).

One interesting feature is the wide moat driven through the rock that separates the castle complex into an east and a west wing, linked by a modern stone bridge.

In addition, the former castle grounds comprise the more than two-hundred-year-old Bismarck Elm, a Harz folktales memorial hall erected from 1928 to 1932, a modern statue of the alleged pagan god Krodo, as well as a restaurant.

He did, however, arouse the disfavour of the local Saxon nobility and the Billung dukes, not only by his Franconian descendance, but also due to the expensive maintaining of his Imperial court.

Intended as a demonstration of power in the Saxon mainland, the extended complex was strategically sited by King Henry's architect Bishop Benno II of Osnabrück providing protection for the nearby Goslar imperial palace and the mines of Rammelsberg.

He even had a sort of family vault built, in which he laid the mortal remains of his brother, Duke Conrad II of Bavaria and his son, Henry, both of whom died young.

According to the chronicler Lambert of Hersfeld, the Saxon Rebellion broke out when on 29 June 1073 several nobles marched against the king residing in the Imperial Palace of Goslar.

The besieging forces led by Otto of Nordheim and Bishop Burchard II of Halberstadt allegedly numbered 60,000 whilst his garrison only had 300 men.

The king initially did not gain much support by the German princes and in the 1074 Treaty of Gerstungen he was forced to agree to slight his castles, including the Harzburg.

In January 1076 Henry had claimed the enfeoffment with Goslar and the Rammelsberg mines in turn for his support against the rebellious Italian cities of the Lombard League.

About 1370 it was occupied by the Welf duke Otto of Brunswick-Göttingen during the War of the Lüneburg Succession and entrusted to his ministerialis Hans von Schwicheldt, against fierce protest raised by the Wernigerode counts.

In the early 15th century the Harzburg was pledged as a fief to the three sons of Hans von Schwicheldt, who turned it into a robber baron castle and ravaged the surrounding Brunswick, Hildesheim and Halberstadt lands.