Burg Stahleck was built above the town of Bacharach around 1100. It was recorded to be in the possession of Goswin von Stahleck in 1134. In 1142, King Konrad III elevated his brother-in-law and Goswin's son Hermann von Stahleck to Counts of Palatine. It was the first large castle north of Bingen on the River Rhine.
In 1194, Agnes, daughter and heiress of his successor, Konrad von Staufen, married Henry the Elder of Brunswick, the son of Heinrich dem Lowen (Henry the Lion) in secret at Stahleck Castle because the two families were in a bitter feud. This caused the castle to pass to the Guelphs and, in 1214, to the Wittelsbach family line under Duke Ludwig I of the House of Wittelsbach.
In 1344, officials enhanced the fortifications in Bacharach by adding walls, towers, and gates.
Stahleck Castle was besieged, conquered, and sacked eight times during the Thirty Years' War. In 1620, the castle and town were taken by Spanish troops until they were evicted by Protestant Swedes in 1632. In 1635 the castle was besieged by Imperial troops under Matthias Gallas until they were ousted by Weimaran soldiers in 1639. In the autumn of 1640, Spanish Troops reoccupied the castle after a 14-day siege. In 1644 the castle was then taken by French soldiers after a 10-day siege and one month later troops from Cologne attacked the castle and forced the French to retreat. The Cologne commander, Constantin von Nievenheimb, ordered the bombardment of the castle instead of capturing it.
In 1666, Electoral Prince Karl I had the castle restored. This was short-lived, as the French reduced the castle to ruins again in 1689 during the War of Palatine Succession.
The Rhenish Association for Landmark Preservation and Landscape Protection bought the ruins in 1909 and began restoration work, creating the youth hostel between 1925 and 1927, restoring the great hall in 1931, and restoring the keep between 1965 and 1967.
Burg Stahleck is not open for visitors but serves as a youth hostel, allowing the castle to be viewed up close from the courtyard. A three meter thick shield wall surrounds one side of the castle with polygonal towers at each end.
Burg Stahleck also has a water filled moat, a rarity in Germany, especially for a hillside castle. The great hall stands on the river side of the castle and the round keep with its cone-shaped roof has a diameter of 7.5 meters.
Castles that are open to the public can be found just south along the River Rhein, including Burg Sooneck and Burg Rheinstein.