Waldnaabtal, Nature reserve in Falkenberg and Windischeschenbach, Germany.

Waldnaabtal is a 182-hectare nature reserve stretching about 6 km along the Waldnaab River from the Hammermühle to the mouth of the Frombach, near Falkenberg in Bavaria. The river has cut a gorge-like valley into the Falkenberger granite massif, leaving fields of boulders in the water, bizarre weathering forms and steeply rising granite cliffs. Erosion hollows and grinding marks on the rock walls show how the river cut into the bedrock as the land rose.

Waldnaabtal was first designated a nature reserve on 22 July 1950; a revised ordinance followed on 24 November 1976. The protected section runs from the Hammermühle to the mouth of the Frombach, covering about 182 hectares, of which 153 lie in Tirschenreuth district and 29 in Neustadt an der Waldnaab. It forms part of the FFH area between Tirschenreuth and Windischeschenbach.

The Sauerbrunnen, a publicly accessible mineral spring on the trail above the Blockhütte, releases water rich in sulphur and carbonic acid that stains the surrounding granite yellow-red. Such Säuerlinge around Tirschenreuth are linked to early volcanic activity; earthquakes and hot sulphur water in the Steinwald are documented historically.

The reserve features several marked hiking trails of varying lengths that give visitors access to different parts of the area. Sturdy footwear is recommended, as some paths can be steep and rocky, especially near the cliff sections.

The Sauerbrunnen is a publicly accessible mineral spring on the trail above the Blockhütte; its sulphur- and carbon-dioxide-rich water stains the surrounding granite yellow-red. Such springs around Tirschenreuth are linked to early volcanic activity, and earthquakes with later hot sulphur water in the Steinwald are historically documented.