Burg Hohenlupfen, Medieval castle ruins on Zeugenberg Lupfen in Talheim, Germany.

Burg Hohenlupfen is a ruined hilltop castle on the Lupfen, a 975.5-metre hill above Talheim. Only its rampart and ditch survive; the square keep, seven by seven metres, is marked by an observation tower, and the line of the 1.2-metre-thick perimeter wall can be read in the ground.

First mentioned in 1065, the castle was the ancestral seat of the Counts of Lupfen. Rottweil troops destroyed it in 1377, but it was rebuilt and then finally destroyed again in 1416 during the Lupfener Fehde on the orders of King Sigismund. The site passed to the Lords of Friedingen in 1437 and to Württemberg in 1444.

The castle served as a power center for the Counts of Lupfen, who ruled their Swabian territories from this location. Today, the site reflects the regional importance of this medieval noble family.

The site sits on a hilltop and offers views across the surrounding landscape while exploring. An observation tower from a later period stands where the original keep once was and helps with orientation.

The keep's footprint measured seven by seven metres, and in 1791 remains of the surrounding wall still stood to a thickness of 1.2 metres. Today only the line of that wall and the moat can be traced in the ground, while an observation tower occupies the presumed site of the square keep.