Ysperklamm, Natural monument and gorge in Yspertal, Lower Austria, Austria

Ysperklamm is a gorge on the upper course of the Große Ysper in the market town of Yspertal, Waldviertel. Over a few kilometres the river drops 300 metres from the rolling high plateau into the Yspertal. A hiking trail crosses numerous bridges, stairs and ladders, and a parallel vehicle-width path runs alongside the gorge.

Timber was floated down the Große Ysper until 1929, when logs were carried as far as the Danube and then on to Vienna by boat and raft. For the "Große Ysperschwemme" the Ödteich pond, created in 1599, was dammed and released by pulling a plug to send a surge of water down the gorge. In the night of 19 to 20 April 1956 the dam broke, draining the 3.5-hectare pond and damaging the paths and bridges; the dam was never rebuilt. The gorge was declared a natural monument (ID ME-028) on 4 December 1952.

The name Ysperklamm comes from the Große Ysper, the river that carved the gorge. Until 1929, wood was floated down the stream to the Danube and then shipped to Vienna; the 1599 Ödteich pond supplied the water surge for the 'Große Ysperschwemme'. The Ysper-Weitental circular trail and the Eisenwurzenweg long-distance path now lead hikers through the gorge.

You enter from a parking area where an information point welcomes visitors. The pathways are built with wooden planks and stairs, so wear sturdy shoes and move carefully on the damp surfaces.

The wooden log flume that carried timber to the Danube operated until 1929. Water released from the Ödteich, an artificial pond built in 1599, flushed metre-long logs down the Große Ysper. The dam broke in April 1956 and was never rebuilt; its overgrown remains lie near the gorge.