Alte Burg, Castle ruin in Oberhausen, Germany

Alte Burg is a ruined hilltop castle on the wooded south bank of the Danube about 2.5 km west of Neuburg's old town. A bow-shaped neck ditch up to 15 m deep, edged by a rampart and an outer ditch, cuts the plateau off from the approach. The oval 100 by 50 m core is dominated on the west by high shield-wall-like outer walls pierced by putlog holes and window openings; only foundations remain of the cross walls, and the few wall remnants of the square bergfried north of the ditch were rebuilt about half a metre high.

The castle was probably built in the late 10th century; a 1007 charter of Henry II mentions a Kemenate of his castle "Nouumburg", likely this site. In 1197 Henry VI granted the office of Neuburg with the castle as a fief to his marshal Henry of Kalden. The Wittelsbachs captured it during the Meraner Fehde of 1246/47, and it was destroyed again in 1386 in the war of Bavaria against the Rhenish League. It was not rebuilt; from 1597 the ruin was quarried for stone for the tower of the Hofkirche.

The site displays medieval defensive building techniques typical of the region. Visitors can see how such structures served as power symbols for local rulers of that time.

The ruin lies about 2.5 km west of Neuburg's old town on the wooded south bank of the Danube, roughly 430 m above sea level; a footpath leads there from Oberhausen. The oval plateau is about 100 by 50 m, and the neck ditch drops up to 15 m, so sturdy shoes are needed. About 300 m southeast, earthworks of a Roman burgus are visible in the terrain.

The few wall remains of the square Bergfried north of the plateau were rebuilt only about half a metre high during conservation work; no tower reconstruction exists. The site also holds a Roman burgus earthwork about 300 metres to the southeast.