Natural wonder Europe
Seljalandsfoss
Seljalandsfoss is a waterfall in Iceland. You can walk around behind the falling water.
Seljalandsfoss is a waterfall in South Iceland, about 62 meters high, Katla UNESCO Global Geopark says. It pours over an old sea cliff that ocean waves cut long ago, when the sea was much higher than it is today, and you can walk around behind it.
Seljalandsfoss (about 62 m; Katla UNESCO Global Geopark) is on the Seljalandsá river, which rises on the western side of the Eyjafjöll range. It falls over a former sea cliff cut by waves during and after the end of the last glaciation, when relative sea level stood much higher; a lava layer caps the cliff over palagonite tuff and breccia.
Photo: Einsir, CC BY-SA 4.0, via Wikimedia Commons
Discover Seljalandsfoss
Seljalandsfoss is a waterfall in Iceland. The water drops into a pool below.
This photo was taken from behind the falling water. You can see a white curtain of water and green land far away.
Seljalandsfoss is in South Iceland, in Katla UNESCO Global Geopark. Its river, the Seljalandsá, starts on the western side of the Eyjafjöll mountains. The water falls about 62 meters into a pool called Kerið, which means the Tub, and you can walk around behind it.
This photo by Einsir was taken on 17 June 2020 from behind the falls. A white curtain of water drops into the pool under an overhanging cliff, with mossy rocks in front and flat green land stretching away.
Katla UNESCO Global Geopark: Seljalandsfoss is on the Seljalandsá, which originates on the western side of the Eyjafjöll range; it is about 62 m high and has formed a plunge pool, Kerið (the Tub). Visitors can walk around behind it. Its neighbor Gljúfrabúi, 40 m high, falls from the spring-fed Gljúfurá.
The photo (Einsir, CC BY-SA 4.0, 17 June 2020) looks out from under the overhanging cliff, past the falling water, to the pool, the outflow stream and the flat lowland beyond.
- Height (Katla Geopark, about)
- 62 m
- River
- Seljalandsá
- Pool below the falls
- Kerið (the Tub)
A cliff cut by the sea
Long ago, the sea came right up to this cliff. Waves cut into the mountains and made it.
Now the sea is lower. Flat land lies in front of the cliff.
Seljalandsfoss falls from an old sea cliff. Katla Geopark explains that during and after the end of the last ice age, the sea stood much higher than it does now, and waves cut into the Eyjafjöll mountains to make the cliffs.
Since then the sea level has dropped. Lowlands formed in front of the mountains, so the old sea cliffs now stand far inland.
Katla Geopark: the cliffs formed during and after the end of the last glaciation, when relative sea level was much higher than now; waves eroded into the Eyjafjöll range. As relative sea level fell, lowlands built out in front of the range, leaving the sea cliffs far inland.
The cliff at the waterfall has a few rock layers: lava at the top, and below it mostly palagonite tuff and breccia of various grain sizes, often finely layered and of different colors.
Fish in the Tub
The water lands in a pool called the Tub.
Fish called sea trout and sea char can be seen in the pool.
The falling water has made a pool at the foot of the falls, called Kerið, or the Tub. Katla Geopark says sea char and sea trout can be spotted in it.
In the photo, green moss covers the rocks around the pool, and flat green land stretches beyond.
Katla Geopark: the plunge pool Kerið (the Tub) holds sea char and sea trout, which can be spotted there.
In the photo, moss covers the boulders and ledges around the pool, and green vegetation covers the lowland that formed in front of the old sea cliffs.
Walking behind the water
You can walk around behind the waterfall. You can look out through the water.
The cliff hangs overhead like a roof.
Katla Geopark says it is possible to walk around behind Seljalandsfoss. From behind, the water falls in front of you like a curtain.
The Geopark also suggests looking at the cliff itself. Its top layer is lava, and below that are rocks called palagonite tuff and breccia, often in layers of different colors.
Katla Geopark notes the walk around behind the falls and recommends admiring the cliffs too: lava at the top over palagonite tuff and breccia with various grain sizes, often beautifully layered.
The photo shows this vantage: the overhang frames the view on the right, and the water curtain falls between the cliff and the pool.
Safe near the water
Stay with a grown-up near rivers and pools.
Check the weather before you go. It can change fast.
The CDC says rivers and lakes can hide dangers such as strong currents, rocks and water you cannot see through. Children should wear life jackets in and around natural water, and a grown-up should watch them closely.
The CDC also says to check the forecast first, because local weather can change quickly and bring strong winds and storms.
CDC drowning prevention: natural waters have hidden hazards (dangerous currents or waves, rocks or vegetation, limited visibility); children should use life jackets for all activities in and around natural water; a responsible adult should supervise closely and constantly; check the forecast, since local conditions can change quickly with flash floods, strong winds and thunderstorms.
Amazing facts
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You can walk around behind this waterfall.
Visitors can walk around behind Seljalandsfoss.
Katla Geopark: it is possible to walk around behind Seljalandsfoss.
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The cliff was made by sea waves, but the sea is now far away.
Seljalandsfoss falls over an old sea cliff that now stands far inland.
The cliff is a former sea cliff, cut when relative sea level was much higher after the last glaciation and now far inland.
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The pool under the waterfall is called the Tub.
The pool below the falls is called Kerið, which means the Tub.
The plunge pool Kerið (the Tub) is where sea char and sea trout can be spotted (Katla Geopark).
Words to know
- sea cliff
- a steep rock face cut by ocean waves
- plunge pool
- a pool dug out at the foot of a waterfall by the falling water
- sea level
- the average height of the surface of the sea
- palagonite tuff
- a rock made of volcanic ash and glassy bits that have changed and hardened
- breccia
- a rock made of broken, sharp-edged pieces stuck together
- geopark
- an area with important rocks and landscapes, protected and shared with visitors
Discovery challenge
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In which country is Seljalandsfoss?
Seljalandsfoss is in the south of which island country?
Katla UNESCO Global Geopark, home of Seljalandsfoss, is in which country?
- Iceland
- Brazil
- Kenya
Show the answer
Iceland
Iceland.
Iceland, in South Iceland.
Iceland (Katla UNESCO Global Geopark).
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What made the cliff the water falls over?
What cut the cliff that Seljalandsfoss falls over?
According to Katla Geopark, what eroded the cliffs into the Eyjafjöll range?
- Sea waves, long ago
- A river of lava
- People with machines
Show the answer
Sea waves, long ago
Sea waves, when the sea was higher.
Sea waves, when the sea was much higher than today.
Waves, during and after the end of the last glaciation, at high relative sea level.
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What is the pool under the falls called?
What is Kerið, the pool below the falls, called in English?
What English name does Katla Geopark give the plunge pool Kerið?
- The Tub
- The Cup
- The Bucket
Show the answer
The Tub
The Tub.
The Tub.
The Tub (Katla Geopark).
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What rock is at the very top of the cliff?
Which rock forms the top layer of the cliff at the waterfall?
Which layer caps the palagonite tuff and breccia at Seljalandsfoss?
- Lava
- Ice
- Sand
Show the answer
Lava
Lava rock.
A layer of lava.
A lava layer (Katla Geopark).
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What should you check before a trip to a waterfall?
What does the CDC say to check before going near natural water?
Why does the CDC advise checking the forecast before water activities?
- The weather forecast
- The moon
- Nothing at all
Show the answer
The weather forecast
The weather.
The forecast, because weather can change quickly.
Local conditions can change quickly, bringing flash floods, strong winds and thunderstorms (CDC).
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For parents & teachers
What children will learn
- Locate Seljalandsfoss in South Iceland.
- Explain how a sea cliff can end up far inland when sea level falls.
- Describe the rock layers in the cliff at the waterfall.
- Explain how to stay safe near rivers and pools.
Recommended ages: 3 to 17 · About 15 minutes
Talk about it
- If the sea was once at the foot of this cliff, what clues might show it?
- Why might a waterfall that you can walk behind feel so different from one you see from the front?
- What could make a path near a waterfall more dangerous in bad weather?
Try at home or in class
- Build a sand cliff in a tray, pour water slowly to make a 'sea' against it, then lower the water and see where the cliff ends up.
- Stack layers of different colored modeling clay and cut through them to see layers like the cliff's lava, tuff and breccia.
Key vocabulary: sea cliff, plunge pool, sea level, palagonite tuff, breccia, geopark
Where these facts come from
- Wikidata , Wikimedia Foundation (CC0 1.0)
- Seljalandsfoss and Gljúfrabúi (geosite) , Katla UNESCO Global Geopark
- Preventing Drowning , US Centers for Disease Control and Prevention
- Seljalandsfoss, June 2020 (Wikimedia Commons file page) , Wikimedia Commons
- Wikimedia Commons , Wikimedia Foundation (Per file (public domain, CC0, CC BY or CC BY-SA); see each media record)
Checked, not yet human-reviewed. Last updated November 1, 2026. Spotted a mistake? Tell us.