Burgruine Aichelburg, castle ruin in Sankt Stefan im Gailtal, Austria

Burgruine Aichelburg is a ruin on a wooded hilltop south of St. Stefan an der Gail. Surviving are two- to four-metre-high sections of the roughly 80 cm thick ring wall and remains of two towers; of the residential building only a small part of the northeast corner stands. The neck ditch is still visible, and a stone memorial column erected around 1900 by Leopold Freiherr von Aichelburg-Labia stands before the northeast entrance.

The castle was built in the 13th or 14th century and first mentioned in records in 1307 as belonging to the counts of Görz family. Over the centuries it suffered destruction by Emperor Friedrich III around 1460, was later rebuilt, burned in 1516, and was finally abandoned after an earthquake around 1690.

The name Aichelburg appears in records in 1432, while the earlier tower was documented in 1307 as "turen bey sand Stephan bey der Geyle". Christoph Viertaler, ennobled in 1507, took the name "von Aichelburg", and the family kept the site for generations. Around 1900 Leopold Freiherr von Aichelburg-Labia set up the stone memorial column at the northeast corner of the approach.

The ruin stands on a wooded spur above the Gailtal, reached on foot from Sankt Stefan an der Gail; the final stretch is steep and uneven. The ring wall, two to four metres high, and the filled-in neck ditch can be examined from outside, as no interior rooms survive. A stone memorial column stands at the northeast corner before the entrance.

The stone memorial column at the northeast corner, in front of the entrance, was put up around 1900 by Leopold Freiherr von Aichelburg-Labia. The castle was already being quarried for stone after its abandonment, and the neck ditch, though filled with rubble, is still visible.