Halser Ilzschleifen, Protected area in Passau and Salzweg, Germany

Halser Ilzschleifen is a 91.5-hectare nature reserve established in 1993 along the Ilz River north of Passau. The river, blocked by a gneiss outcrop, cuts two meanders through softer shale of the Aicha-Halser-Nebenpfahl. The narrow, wooded valley has sunny rock heads and slopes above the river; the Hals district with its castle ruin lies within the reserve.

This protected area was established in 1993 after a citizens' movement successfully blocked construction of a bridge connecting major highways. That decision preserved the land in its natural state.

The reserve takes in the Passau district of Hals, where the ruins of Hals Castle stand on a rock spur above the river. The castle's rocks shelter wall lizards, smooth snakes, dwarf elder-leaved irises and pellitory of the wall. The name Hals refers to this narrow neck of land between the Ilz meanders.

An 11-kilometer marked hiking trail starts from the parking area at Passau-Hals and traverses the entire reserve on clearly marked paths. Walking is the best way to explore, and sturdy footwear is advised since paths can be steep and slippery in places.

The reserve is home to around 133 moss species and the woolly spurge, a plant that grows nowhere else in Germany. This botanical rarity draws nature researchers and plant enthusiasts to the area.