The Ahja River Valley Landscape Protection Area was created in 1957. The protected area includes the middle course of the river (18 km along the river), where the water flows over gravelly blockfield rapids in a meltwater valley 200–400 metres’ wide and up to 30 metres’ (40 in some places) deep. The protected area covers 1115.5 ha.
On the high, steep slopes of the meltwater valley, you can see beautiful cross-bedded sandstone outcrops dating back to the Devonian Burtnieki stage, which in this region are called pae and taevaskoda (heaven’s hall). There are more than 40 outcrops here. The smaller ones span a few metres, whereas the largest and best-known – Large Taevaskoda – is 20 metres’ high and 150 metres’ long.
The protected area is home to several rare and endangered species: the Pleurospermum austriacum, the smooth crosswort, the witches cauldron, the common kingfisher, the thick shelled river mussel, the spined loach, the European bullhead, the green snaketail and the Eurasian otter.