Glymur: Iceland's Highest Waterfall Hike

Standing 196 metres tall in the dramatic gorge of Botnsdalur, Glymur commands respect as Iceland's tallest waterfall—a thundering testament to the raw power of glacial meltwater carving through ancient basalt. This remarkable cascade, fed by the river Botnsá as it plunges into Hvalfjörður, offers one of Iceland's most rewarding yet challenging day hikes, demanding proper preparation and respect for Iceland's unforgiving terrain.

The Geological Marvel of Glymur

Glymur's extraordinary height results from the dramatic topographical contrasts of the Hvalfjörður region, where the Botnsá river has carved a deep gorge through layers of tertiary basalt over millennia. The waterfall sits within a narrow canyon system that extends deep into the Glymsgil ravine, creating the perfect conditions for this spectacular drop.

The basalt formations surrounding Glymur date back approximately 10-15 million years, formed during intense volcanic activity in this region. These layered rock faces, visible throughout the hike, tell the story of repeated lava flows that built up Iceland's foundation during the Tertiary period. The river itself originates from Hvalvatn lake, carrying glacial sediment that gives the water its distinctive grey-green hue.

The Complete Hiking Experience

Getting There and Access

The trailhead lies 7.2 kilometres from the Ring Road (Route 1) along Route 47, following signs to Botnsá. From Reykjavík, the 47-kilometre drive takes approximately 50 minutes via the Hvalfjörður tunnel (toll: 1,000 ISK, roughly €7). Park at the designated area near the bridge over Botnsá—space for roughly 20 vehicles, though this fills quickly during peak season (June-August).

The nearest facilities are at the N1 petrol station in Borgarnes, 35 kilometres away, making this essential for fuel, food, and emergency supplies. No services exist at the trailhead itself.

The Trail: A Technical Challenge

The complete circuit spans 7.4 kilometres with an elevation gain of 540 metres, typically requiring 4-5 hours for experienced hikers. This is emphatically not a casual walk—the route demands scrambling, river crossings, and navigation across unmarked terrain.

**First Section (0-2.1km):** The trail begins with a gentle ascent through birch scrubland before reaching the first river crossing. Here, a fallen log serves as the primary crossing point—often slippery and requiring careful balance. Alternative crossing points exist upstream but add considerable distance.

**The Ascent (2.1-3.8km):** Following the river crossing, the path climbs steeply through loose scree and requires occasional scrambling using fixed ropes. The terrain becomes increasingly technical, with several exposed sections where proper hiking boots prove essential. Ancient stone cairns mark the route, though visibility can disappear rapidly in changing weather.

**Summit and Viewpoint (3.8km):** The effort rewards hikers with an unobstructed view down into Glymur's gorge. The perspective from above reveals the waterfall's true scale—the 196-metre drop appears almost impossibly steep, with the Botnsá river creating a silver thread far below.

The Descent Challenge

The return journey offers two options: retracing the ascent route or completing the full circuit via the cave system. The circuit option adds technical difficulty, requiring passage through Þvottahellir cave—a narrow opening that some hikers find claustrophobic. This route includes additional river crossings and unstable terrain, making it suitable only for confident hikers with proper equipment.

Seasonal Considerations and Safety

Optimal Timing

June through September offers the most reliable conditions, with daylight extending until 23:00 during summer months. However, even summer weather remains unpredictable—temperatures at the summit can drop to 5°C whilst Reykjavík enjoys 15°C sunshine.

Spring (April-May) brings increased water flow, making river crossings dangerous or impossible. Autumn (October) offers dramatic lighting and fewer crowds but significantly increases weather risks. Winter access becomes nearly impossible due to snow, ice, and reduced daylight.

Essential Safety Measures

Weather conditions change rapidly in Hvalfjörður, with fog descending within minutes. The Icelandic Met Office (vedur.is) provides essential weather updates—never attempt this hike in forecast winds exceeding 15 m/s or during poor visibility.

Emergency equipment should include: GPS device or smartphone with offline maps, emergency shelter, first aid kit, emergency food for 24 hours, and headlamp with spare batteries. The nearest hospital is Landspítali in Reykjavík, 47 kilometres away.

Mobile phone coverage exists sporadically along the route—emergency services (112) can be contacted from most positions, though response times to this remote location extend to 60-90 minutes minimum.

Planning Your Glymur Adventure

Physical Requirements

This hike demands genuine fitness and hiking experience. The technical river crossings, scrambling sections, and exposure to weather make it unsuitable for children under 14 or anyone uncomfortable with heights. Previous experience with unmarked mountain trails proves invaluable.

Equipment Essentials

Waterproof hiking boots with ankle support are non-negotiable—the terrain includes wet rocks, loose scree, and potential stream crossings. Layered clothing systems work best, with waterproof outer shells essential regardless of forecast. Hiking poles significantly aid stability during river crossings and steep sections.

Alternative Perspectives

For those unable to complete the full hike, the first 1.5 kilometres offers excellent views of the lower gorge and provides a taste of the landscape without technical challenges. Photography enthusiasts should note that optimal lighting occurs during morning hours (09:00-11:00), when sunlight penetrates the deep gorge.

Glymur represents Iceland at its most magnificent and uncompromising—a landscape that rewards preparation and respect whilst punishing overconfidence. This extraordinary waterfall offers an authentic encounter with Iceland's geological power, far removed from the accessible attractions of the Golden Circle, demanding everything a hiker can give whilst delivering memories that endure long after the challenging return to civilisation.

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