Johannisberg, also known as Johannesberg, is a manor located in the eponymous village on the Bishofsberg hill on the northern bank of the Rhine, west of Wiesbaden. This area is now part of the city of Geisenheim.

The castle was previously the site of a medieval Benedictine monastery, which was destroyed during the Reformation. The estate is situated in the Rheingau region, known for its winemaking traditions, and is surrounded by the oldest Riesling vineyards.

In the 17th century, the estate belonged to the Schönborn family. The modern building was laid out in 1716 by the prince-bishop of Fulda. After the Napoleonic Wars, the castle came into the possession of Austrian Chancellor Metternich.

In 1942, Johannisberg was destroyed during the Allied bombing of Mainz. After the war, it was restored by the last Prince Metternich and his wife Tatiana. They rebuilt the basilica, which now serves as a venue for a music festival.

The current owners, descendants of August Etker, position Johannisberg as a center for traditional winemaking. Visitors are offered tours with tastings, a wine bar, a shop, and the opportunity to visit the wine cellars.