Múli is an Icelandic word for a mountain spur — the blunt end of a ridge where it drops toward the lowland. Gljúfur is a canyon. Múlagljúfur is the canyon of the mountain spur, named for the shoulder of Öræfajökull it cuts into. Say it MOO-la-GLYOO-vur.
Names here describe what a farmer needed to know: which ridge, which water, which way through. Hangandifoss is the hanging fall. Fosslækur is the waterfall brook. Nothing in the naming is decorative.
You'll sometimes see "Mule Canyon" online — a mistranslation. No mules involved.
Everything you see was made by water leaving the ice. Meltwater off Öræfajökull has run this line for millennia — steady summer streams grinding down, then the occasional jökulhlaup, a glacial outburst flood that moves boulders and rearranges a valley in a day. Between them they have cut roughly two kilometres into volcanic rock.
The walls are reported up to about 400 metres in the upper canyon. They hold moss because the rock is soft, the air is wet, and nothing grazes a vertical face. The result is a gorge that looks tropical for six weeks a year in a country that is mostly rock and wind.
An ice-covered stratovolcano, and the source of every drop of water that cut the canyon. It erupted in 1362 — Iceland's most destructive eruption, which emptied the district and gave Öræfi its name — and again in 1727.
Its rim carries Hvannadalshnúkur, the highest point in Iceland at 2,110 metres.
One is handed to you at the main viewpoint. The other has to be earned on the upper rim.
Roughly 123 metres of water dropping off the east wall in a single ribbon, fed by the Fosslækur stream. In low flow it thins to a thread; after rain it doubles in width and the spray reaches the path.
It is one of Iceland's tallest waterfalls, and it is not signposted anywhere.
About 101 metres of stacked tiers at the canyon head, on the Rótarfjallsá. Only around 54 metres of it is visible from any one place — the rest is folded into the rock.
You have to walk the upper rim to see it at all, which is why most photographs of Múlagljúfur do not include it.
The moss is the canyon's signature and its most fragile part. It grows on a thin skin of soil that took a long time to accumulate, and a single boot print through it can stay visible for years. Recovery is measured in decades, not seasons. Stay on the worn path.
Fulmars nest on the cliffs from May into August, several kilometres inland, using the updrafts the canyon generates. Sheep graze slopes that look impossible from the other side. Low birch, angelica and summer wildflowers fill the sheltered pockets where the wind cannot reach.
The cliffs are a nursery — give nesting birds space and keep drones grounded in season.
| Season | Character | Light | Access |
|---|---|---|---|
| Summer | Saturated greens, full flow in both falls, birds on the cliffs | Near-24-hour light; golden hour lasts most of the night | Open. 2WD reaches the lot in dry conditions |
| Autumn | Moss turning bronze, first snow dusting the rim | Low and directional; short, strong golden hours | Open. Wet ground; higher clearance advisable |
| Winter | Icy runs down the walls, falls partly frozen | Four to seven hours of daylight | Road unmaintained; experienced parties only |
| Spring | Heavy meltwater, muddy path, moss waking up | Lengthening fast; clear mornings | Opening up; streams run high at the crossings |