Zgornja Idrijca Nature Park

Zgornja Idrijca Nature Park, the Upper Idrijca, is a protected landscape of forested hills, narrow river valleys and steep gorges above the town of Idrija in western Slovenia, one of Slovenia’s quietest corners. The Idrijca River runs through it, joined by tributaries including the Belca, and the area is part of the Idrija UNESCO Global Geopark, which was set up to protect and explain both the geology and the human heritage of the mercury-mining district. Formally the area is known as a landscape park, but visitors will find it described under the nature park name too.

The scenery is the main attraction. The river has cut into the rock to form tight gorges and shaded pools, and the hills around are covered in dense beech, fir and spruce forest. The climate here mixes Mediterranean influences from the nearby coast with Alpine ones from the mountains, and the plant and animal life reflects both, with rare plants on the cliffs and a large number of species in the forest and along the water. Trails of varied length and difficulty run through the park, suitable for walkers and for experienced cyclists, and they are generally quiet outside the busiest summer weekends.

The forests also tell a story about Idrija's past. Idrija’s mercury mine in town needed huge amounts of timber for shoring up its shafts and for fuel, and the woods of the upper Idrijca were the source. To move the logs, local engineers built water-retention dams known as klavže, which were opened to flush floating timber down the river to the town. Some of these stone dams survive as striking monuments in the valley, and they are among the best reasons to explore the area on foot. The valley's geology is also worth attention: the rocks include sedimentary layers rich in fossils as well as older volcanic material, and the Geopark interprets them through its trails and displays.

Fishing draws anglers to the river, which has a good reputation for trout, though fishing here requires a permit and follows local rules. Swimmers and picnickers find quiet pools in summer, but the water is cold and conditions change quickly after heavy rain, so care is needed near the gorge walls.

A good first stop is the Idrija Geopark Visitors' Centre in town, where staff can give maps and advice on trails. Many people combine a day in the park with Idrija's other sights such as the Idrija Mercury Mine, Gewerkenegg Castle, the Municipal Museum and the local Idrija lace tradition, and the Wild Lake (Divje Jezero) is a short drive away.