The fortress located on a limestone plateau served to control the northern border of the bishopric and the trade routes from Halberstadt to Braunschweig and Hildesheim.

At the same time, Hornburg, thriving from the cultivation of humulus (hop) for beer brewing, was surrounded by a town wall including five gates.

During the Thirty Years' War Hornburg was occupied by the Imperial field marshal Johann Tserclaes von Tilly in 1626, but conquered by Swedish troops in 1630.

The current building is a reconstruction on a private initiative or Georg Lüdecke in 1927, based on an engraving by Merian from around 1650 with plans by Bodo Ebhardt.

With the secularization of the Halberstadt bishopric in 1648, Hornburg fell to the electors of Brandenburg and after the 1815 Congress of Vienna it became part of the Prussian province of Saxony.