The ruins of Dreienburg Castle stand on the spur of the Dreienberg, which juts out into the valley of the Stärkelbach to the east. From here you have a wide view of the Werra valley and the Kuppenrhön, including Landeck Castle. 

The Dreienberg is the northernmost mountain in the Rhön or Vorder- und Kuppenrhön, located near the municipality of Friedewald in the district of Hersfeld-Rotenburg in the state of Hesse. The name of the table mountain comes from its three elevations on the plateau. The main peak in the north is 525 meters high. The Linsenkuppe in the south reaches a height of 515 meters and the Friedewalder Kuppe in the west is 511 meters high. The mountain is surrounded by the districts of Lautenhausen, Hillartshausen, Motzfeld and the Weißenborn farm.

The Dreienberg is located at the point where the Fulda and the Werra come closest to each other before their confluence.  

The ruins are located on the "Dreienberg" premium hiking trail.