Idrija is my grandmother's town: home of the world's second-largest mercury mine, a UNESCO World Heritage site, and of the žlikrofi people have always eaten here. What fewer visitors know is that the whole Idrija countryside is also a UNESCO Global Geopark criss-crossed by 24 themed hiking and cycling trails: mining water channels, a lake of legend, monumental « pyramid » dams, a First World War railway. Here is my pick for walking and riding around the mercury town — and properly earning your plate of dumplings.
The essentials at a glance
- Where: Idrija and its plateaus, about an hour's drive west of Ljubljana.
- What: 24 marked geopark routes — from an easy one-hour walk to a 27.5 km bike loop.
- Must-dos: the Rake trail to the Wild Lake (easy), the klavže cycling loop up the Idrijca valley, the WWI Feldban trail.
- Info and maps: geopark visitor point, Prelovčeva ulica 5, Idrija (+386 5 37 43 916), mobile app and interactive map on geopark-idrija.si.
- The 2026 weekend to aim for: Saturday 22 August, the žlikrofi festival in Mejca park — hike in the morning, dumplings in the afternoon.
On foot: three trails that tell Idrija's story
The Rake trail and the Wild Lake (2.5 km, easy)
Photo: Divje jezero © Tuoermin, Wikimedia Commons, CC BY-SA 4.0.
The finest introduction. From the centre of Idrija you follow the Rake, the water channel built in the late 16th century (stone-lined in 1776) to power the mine's machinery, in the footsteps of 18th-century naturalists — Scopoli, the mine's physician, has his memorial garden at the start. Footbridges over the Idrijca, the giant kamšt waterwheel, and via a suspension-bridge detour, the showpiece: Divje jezero, the « Wild Lake », an emerald karst spring tucked beneath a cliff and Slovenia's first « museum in nature ». Its outflow, the Jezernica, is officially Slovenia's shortest river: 55 metres. Allow 45 minutes each way on flat ground; you can continue towards Idrijska Bela for another hour.
The mercury route to Gore (9 km, demanding)
Until 1850, most of Idrija's mercury left town on this mule track, bound for Vrhnika and on to Trieste. It's a stiff climb (510 m of elevation gain) from the centre, past the miners' houses of Rudarska ulica, up to the Raufnk viewpoint with its plunging view over the Idrija basin, then the Turška noga rock and the church of Mary Magdalene in Gore. Three and a half hours to understand, with your legs, what « a mining town at the bottom of a hole » really means.
The Feldban, the Great War railway (10 km, demanding)
After the Austro-Hungarian withdrawal to the Soča in August 1916, two narrow-gauge railways were built across the Trnovo forest to supply the front — including a branch towards Idrija with a cableway near the Wild Lake. The Feldban served only until the Caporetto breakthrough on 24 October 1917; today's trail starts from the Divje jezero car park, passes a 25-metre tunnel and climbs twelve cable-protected switchbacks above the valley. Three hours in the back-country of the Isonzo Front.
By bike: plateaus, klavže and hilltop villages
The upper Idrijca valley and the klavže (27.5 km)
The geopark's finest bike loop starts at Podroteja (the Divje jezero car park) and follows the Idrijca through the Zgornja Idrijca landscape park: the Strug tectonic window, a swim at Lajšt, where the Idrijca meets the Belca — the locals' summer spot —, then the Belčne and Putrihove klavže, the monumental stone dams nicknamed the « Slovenian pyramids »: they stored water to flush timber down to the mercury mine. Allow 2 hours, 364 m of climbing, gravel after the first kilometre — a gravel bike or MTB is essential, and as the loop isn't waymarked, load the GPX track from the geopark's map.
Vojsko, the roof of Primorska (26.5 km)
A steady climb leads to Vojsko, the highest village in Primorska, on its plateau at over 1,000 metres: meadows, remote farms and, on a clear day, views from the Julian Alps to the Adriatic. The catalogue's other loops — the Kanomlja valley, the Završnica plateau, Godovič « in the tracks of prehistory » — can be picked to match the day's legs among the geopark's 24 routes.
Practical tips for 2026
Start at the geopark visitor point (Prelovčeva ulica 5, next to the Idrija tourist office, +386 5 37 43 916) for maps, advice and trail conditions. The interactive map and all 24 route sheets are online, and the geopark has its own mobile app. Some routes are only partially waymarked — a GPS track is your friend. In summer, pack swimwear for Lajšt and proper shoes for the Feldban (cables and scree). A car remains the easiest way to get around: my Slovenia car rental guide applies.
The 22 August plan: hike in the morning, feast in the afternoon
If you're in the area on Saturday 22 August 2026, it's the day of the žlikrofi festival in Mejca park: the perfect combination is a morning on the Rake trail to the Wild Lake, a tour of the Anthony's Shaft mine gallery, then an afternoon among the food stalls — dumplings taste better earned. Idrija slots easily into a Slovenia road trip between Ljubljana and the Soča Valley, and holds a proud place among my hidden gems in Slovenia.
Idrija Geopark FAQ
What is the best easy hike in Idrija?
The Rake trail to the Wild Lake (Divje jezero): 2.5 flat kilometres along the 16th-century mining water channel, 45 minutes each way, with footbridges over the Idrijca and a suspension-bridge detour to the lake. It's the best introduction to the geopark and easily done with children.
What are the Idrija klavže?
Monumental stone dams built on the Idrijca and its tributaries to store water and float timber down to the mercury mine — hence their nickname, the « Slovenian pyramids ». You reach the Belčne and Putrihove klavže by bike on the upper Idrijca valley loop (27.5 km, gravel).
Can you swim in the Idrija Geopark?
Yes, at Lajšt, the natural bathing area where the Idrijca and Belca rivers meet, inside the Zgornja Idrijca landscape park. The water is brisk even in August — locals will confirm it with a smile. The Wild Lake itself is a protected natural monument: for looking, not swimming.
Do I need a mountain bike for the geopark's cycling routes?
For most of them, yes: the Zgornja Idrijca loop turns to gravel and forest tracks after the first kilometre, and the plateau loops mix asphalt and gravel. A gravel bike or (e-)MTB is the right choice; road bikes are best kept to the Vojsko and Kanomlja roads.
How many days should I spend in Idrija?
Two days are ideal: one for the UNESCO town (Anthony's Shaft mine, Gewerkenegg Castle, bobbin lace, žlikrofi), one for the geopark trails — the Rake and Wild Lake at a minimum, the Feldban or the klavže if your legs are good. On Saturday 22 August 2026, add the žlikrofi festival in Mejca park.
Patrick Faust
French expat in Slovenia since 2004. Founder of e-Slovénie, a Slovenia travel guide. Learn more →