Geopark Idrija

The area of the Idrija Geopark includes the entire municipality of Idrija, which lies in western Slovenia, more precisely, in the western pre-alpine foothills. Even more precisely, the park is located in the region of the Idrija and Cerkno hills.

Area: 294 km2

Population: 11,800

Average elevation: 746.4 m.

- Geomorphology

- Geology

- Watercourses

- Climate

- Soil

- Vegetation

- Inhabitants

- Economy

- Tourism

- Traffic


The area of the Idrija Geopark has an extremely diversified morphology. Visitors can marvel at the high-lying karst plateaus, which have no surface flowing waters, but are surprisingly abundant in caves, abysses and sinkholes. These plateaus lie at elevations ranging from 650 to 800 metres; only the Vojsko plateau is up to 1,100 metres high. From these Karst plateaus, the terrain descends steeply towards narrow river valleys.

In the western part of the Idrija Geopark, one finds the isolated karst on Vojsko plateau, in the surroundings of Čekovnik, and in the area of Krnice and Šebrelje.

To the east are the Ledinska, Vrsniška, Dolska and Zavraška plateaus, which belong to the Rovtarsko hills. The area has no surface flowing waters; even surface karst phenomena are very rare. The most frequently found karst phenomena are sinkholes.

The most typically karst area is in the southern part of the Idrija Geopark, where at first glance one notices distinct sinkholes on the Črni vrh and Zadlog plateaus; this area also features some highly interesting abysses and caves. Among the most impressive karst phenomena is the more than 900 metre-long Habe shaft and the huge entrance to the Golobeja Cave in the middle of a forest near Predgriže.

The plateaus are separated by narrow, deep river valleys. The fluvial (river) relief at confluences and the large gravel deposits have created conditions for the development of settlements: the town of Idrija was established at the confluence of the Idrijca River and Nikova stream, Spodnja Idrija sprung up at the confluence of the Idrijca River and Kanomljica stream, and Idrijska Bela developed at the confluence of the Idrijca River and Belca stream.


The predominant rocks in the area of the Idrija Geopark date from the middle era of Earth's history (Mesozoic), primarily from the oldest, Triassic period. Rocks from Jurassic can be found along the southern edge, while the area in the direction of Cerkno features rocks from the old era of Earth's history (Paleozoic). The most commonly found rocks are dolomite and limestone, also frequent are shale, siltstone with chert fragments, and sandstone.

An exceptional geological particularity is the Idrija fault, which is one of the largest in this part of Europe and is also »to blame« for the formation of the mercury ore deposit. Another geological particularity is a number of tectonic windows. There is even a triple tectonic window in the Bratuševa grapa ravine at Kanomlja, where the Čekovnik nappe, Koševnik nappe and an autochthonous basement are exposed beneath the Idrija nappe.

Read more about the geology of the Idrija Geopark here


The main watercourse in the Idrija Geopark is the Idrijca River in a length of 48 kilometres with its major tributaries: the Belca, Zala, Nikova, Kanomljica and Cerkniščica streams. The Idrijca River basin belongs to the Adriatic Sea drainage basin. Here one finds pools and cascades, and its waters are fairly clean. The river rises at Mrzla Rupa, along the edge of the Vojsko plateau, just below the watershed between the Idrijca River and Trebuščica stream (which is its tributary), at an elevation of 960 metres. The Idrijca discharges into the Soča River at Most na Soči, at an elevation of 170 metres.

The Idrijca River has its first peak discharge in autumn (November), and its second in spring (April). Its base discharge is in summer (August), while its second, considerably less distinct base discharge is in winter (January). These data indicate that a continental variant of the rain-snow regime prevails in this river.

The largest hydrological curiosity of the Idrija Geopark is Divje jezero (Wild Lake), which lies between the Kobila dam and the confluence of the Idrijca River and Zala stream, along the road leading from Idrija in the direction of Idrijska Bela. Wild Lake lies at an elevation of 330 metres. This is a special type of karst spring known as a Vaucluse spring, named after Vaucluse near Avignon, France, where this type of spring was first described. Waters flow into Wild Lake from Idrijski Log, Koševnik, Črni vrh plateau, perhaps even from part of Križna gora and Javnornik, Mrzli Log, Široka dolina, Kanji Dol, and Vodice. Wild Lake has a discharge area of 65 km2.


The Idrija Geopark has a very humid climate typical of the Alpine and Dinaric highlands – a moderate continental climate. The average temperatures in October are higher than in April, the precipitation regime is sub-Mediterranean, and the average annual precipitation ranges from 1,300 to 2,800 milimetres. The area has an annual precipitation of approximately 2,500 milimetres per year. The highest precipitation is in November (first peak), and the second peak is in spring. The lowest precipitation is in winter (February) and in summer (July). Temperature inversion is a frequent phenomenon in winter, cold air with fog accumulates on the bottom of basins, while higher lying areas have warm and clear weather.


Shallow and medium-deep brown soils have developed on the dolomite and limestone base. In some areas, rendzina has appeared on dolomites. The slopes are predominantly covered with rendzina and grey-brown humus soil. Pseudogley or acidic brown soil with podzol and pseudogley has developed in the karst sinkholes and other depressions. Acidic brown soil covers the siliceous sandstones and tuffs.


The Idrija hills are predominantly covered by forest communities of beech and hop-hornbeam. Among the forest communities are thermophile forests of beech and hop-hornbeam, islands of fir and beech forests, mountain beech forests and, more rarely, acidophile fir and round-leaved bedstraw forests. Forests cover around 70 % of the entire surface.

Prevalent among trees are beech, hop-hornbeam, spruce, fir, oak, sweet chestnut, mountain maple, and common ash.

The special plants found in the Idrija Geopark include Blagay's Daphne, Alpine Butterwort, Hairy Alpenrose, navadna slejka, Twoflower Violet, Scopolia, Hacquetia, Bear's Ear, Idrija Primrose, Alpine Snowbell, Alpenrose, Lily of the Valley, Common Houseleek, Large Red Dead Nettle, etc.


In past years, a constant trend of slight decline in the number of inhabitants is present in the Idrija Geopark area. The current negative population growth is largely due to the negative natural population growth, and partly due to the depopulation of the municipality.

The average population density in the Geopark is low and amounts to less than 41 inhabitants/km2, which is more than twice below the Slovenian average (Slovenia: 97 inhabitants/km2). The most densely populated part of the municipality is the Idrijca River valley, the location of the two largest settlements in the Geopark area, i.e. Idrija and Spodnja Idrija. These are highly urbanised settlements in which 63% of the municipality's entire population live. All other settlements are mostly scattered throughout the hill-covered parts of the municipality and are much smaller in size. The population density is also lower here. The most sparsely populated are the southwestern and southern parts of the Geopark area.


The history of Idrija is, since its origin, marked by mining. Thanks to the discovery of mercury ore, this remote area acquired a traffic connection with major towns and cities, a mainroad through Zala, Godovič and Logatec to Ljubljana, while rail or motorway links were not possible due to the narrow valleys and lack of space. Anthony's Main Road was opened in 1500, and is today open to visitors as a tourist mine. Ore extraction lasted until 1987, when a procedure for the shutdown of the mercury mine was initiated.

Idrija recovered quickly after the mine's closure, despite having lost a large company. After 1975, a number of electric and metal-processing plants (Kolektor and Rotomatika) were opened, as well as small companies. Both of these large concerns export a considerable share of their output abroad. The Idrija Geopark area also has large timber stocks that contribute to the subsistence and development of the wood industry (Iles in Spodnja Idrija), which is today less competitive because the wood market is saturated with products from countries with cheaper manpower (Slovakia, Poland). 

One of the most important and recognisable crafts in the Idrija region is lacemaking. Bobbin lacemaking began to be practised in Idrija in the late 17th century, and spread to the Cerkno region, Trnovo plateau, the Škofja Loka hills, and Baška grapa. During Idrija's mining period, housewives made lace to help support their families. Lace articles were sold to rich farmers, churches, and even abroad. Lace is today an important recognisable component of the Idrija Geopark.

Agriculture was once quite developed in higher lying areas, on plateaus, despite the large surface inclinations, severe winters, and not too fertile soil. Today, agriculture is mostly being abandoned, fields and meadows are becoming overgrown. Large farms have remained only at more favourable locations, while young people are seeking work in the valley or in major towns. The largest profits of farmers are today generated through the sale of milk and meat, and by forestry. In recent times, horse breeding, sheep breeding and beekeeping are gaining popularity. Slovenia's entry in 2004 into the European Union, which has a favourable agricultural policy, has helped to financially support agriculture and preserve the population and cultural landscape in areas that are less favourable for farming.


The rich technical and cultural heritage left by Idrija's mercury mine, which operated for 500 years, together with the area's exceptional natural heritage, provide a good basis for the successful development of tourism. Thanks to its numerous natural, cultural, technical and ethnographic attractions, the Idrija Geopark has enormous possibilities for development.

In Idrija and its surroundings, tourists can visit interesting technical monuments that are unique in Slovenia and on an international scale. The largest tourist attractions in the surroundings of Idrija are the klavže water barriers, Wild Lake, the kamšt water wheel, technical museum, Gewerkenegg Castle/Museum, Anthony's Main Road, Idrija miner's house, demonstration of lacemaking and preparation of žlikrofi (culinary specialty), and the partisan printing shop on Vojsko plateau. In the surroundings of Spodnja Idrija, visitors can admire the Kanomlja klavže (water barriers) and the Kenda Manor. In 2011, Hotel Jožef was opened in Idrija. According to data provided by the Tourist Information Center, the largest number of tourists visit Idrija in summer.

The vast natural surroundings in higher lying parts of the Idrija Geopark provide excellent opportunities for recreational tourism, particularly cycling and hiking in summer. In winter, alpine ski pistes and cross-country trails on the Vojsko and Črni vrh plateaus are open to skiers in favourable snow conditions.


Owing to its relief characteristics, the Geopark has a slightly unfavourable traffic position. The main and most heavily burdened road connection through the area is a newly reconstructed state mainroad, a section of which is a three-lane road enabling higher travel speeds. This road leads to the  Geopark from the direction of Ljubljana through the village of Godovič, descends along the narrow valley of the Zala stream to Idrija, and then continues along the narrow valley of the Idrijca River in the direction of Cerkno and Tolmin, and on towards the Posočje region. This traffic road branches off onto three important regional state roads in the area of the Geopark (towards Ajdovščina, towards Žiri, and through Kanomlja).

Access to the Geopark is also possible from various directions via narrow local roads, which form an extensive road network throughout the Geopark.

Access by train is not possible due to the absence of a railway network in the area. The closest railway links are in Logatec and at Most na Soči. The closest airport, the Jože Pučnik Ljubljana International Airport at Brnik, is located approx. 80 km from the area. The Ronchi dei Legionari Airport, situated in the Friuli-Venezia Giulia region of Italy, is also 80 km from the Idrija Geopark.



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