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Tröllafoss waterfall

MosfellsdalurWaterfallFree entryShort hike
Written by locals at Iceland Travel Guide · Checked by Heiða · Updated October 2026
TRÖLLAFOSS IN SHORT

Tröllafoss (“Troll Waterfall”) is a 20-metre waterfall on the Leirvogsá river in Mosfellsdalur valley, not far from Reykjavík. It is free to visit, reached by a short walk from a small parking area, and is a quiet alternative to the busier waterfalls further from the city. Allow about an hour, including the walk.

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Quick factsHistoryGetting thereDirectionsBest time to visitSafety tipsFacilitiesMapNearbyWhere to stayFAQ

About Tröllafoss

Tröllafoss drops in a single fall of about 20 metres over a dark basalt cliff on the Leirvogsá river, in the quiet Mosfellsdalur valley just outside Reykjavík. Unlike Gullfoss or Seljalandsfoss, it sees relatively few visitors, mostly locals and people looking for a short walk close to the city.

The name comes from rock formations on the cliff face beside the falls, which are said to look like the face of a troll. It's the kind of small local landmark that gives the place its character: not dramatic in scale, but a pleasant, easy escape into nature without a long drive.

Iceland has many famous waterfalls and a few that have almost been forgotten. Tröllafoss is one of the second kind, a little-known waterfall visited mostly by people who live nearby. In Iceland nearly every hill, crack and stream has a name with a story behind it, and this one is no different.

Quick facts

HeightAbout 20 m
RiverLeirvogsá
RegionWest Iceland, Mosfellsdalur valley
From ReykjavíkAbout 20 km, around 25–30 minutes by car
EntryFree
Opening hoursOpen all year
Time neededAbout an hour, including the walk

The troll in the cliff

Tröllafoss takes its name from a rock formation on the cliff beside the falls that many people say looks like the face of a troll looking out over the water. Icelandic folklore is full of trolls said to live in rocks and cliffs, turned to stone if caught out in daylight, and this waterfall's name fits that tradition, even without a specific saga attached to it.

How to get to Tröllafoss

By carFrom Reykjavík, take Route 49 and Route 1 (Vesturlandsvegur) towards Mosfellsbær, then follow Route 36 (Þingvallavegur) into Mosfellsdalur. Turn off towards Skeggjastaðir farm, and just before the farm turn right onto the gravel track Tröllafossslóði, which leads to the parking area.
Hiking thereFrom the small parking area, a walking path follows the Leirvogsá river to the falls. The ground can be uneven and there are a couple of stream crossings, so waterproof shoes help.
By public transportThere is no public transport directly to Tröllafoss.

This is a local, lightly signed spot rather than a set-up tourist site, so take note of where you park and expect a natural, unpaved path rather than boardwalks.

Directions to the waterfall, step by step

Tröllafoss is close to the city but not well signed, so it helps to know the turns before you set off.

Step 1: Reykjavík to MosfellsdalurLeave Reykjavík on Route 49 and Route 1 north to Mosfellsbær, then take Route 36, Þingvallavegur, into the valley.
Step 2: Towards SkeggjastaðirThe waterfall is close to Skeggjastaðir farm, so use the farm as your marker. Just before you reach it, turn right onto Tröllafossslóði.
Step 3: The sign and the parking areaAfter a few minutes on the track you will see a sign for Tröllafoss. A few minutes more brings you to a junction that serves as the parking area. Leave the car here.
Step 4: The walk and the descentWalk the rest of the way along the river. Near the falls the path reaches a steep slope down to the water. The rock here is loose and stones often fall, so go slowly or enjoy the view from the top.

Do not block the track or farm gates when you park, and give yourself a few minutes at the falls to take in the valley around it.

Best time to visit Tröllafoss

SummerThe easiest time to walk in, with dry paths and good light. The most popular season with locals.
WinterThe path can be icy or snow-covered and stream crossings harder to judge, so take extra care or wait for a clearer day.

Safety and practical tips

  • Wear waterproof shoes; the path crosses small streams and can be muddy.
  • There are loose rocks near the falls, so keep a safe distance from the edge.
  • Take care on the steep slope down to the river; stones come loose easily.
  • This is an unmarked, local spot, so bring a map or offline directions.
  • Look for the troll's face in the cliff beside the falls; whether you see it depends on how you look.
  • Combine it with a visit to Mosfellsdalur's farms and horse riding tours in the same valley.

Facilities and accessibility

There are no facilities at Tröllafoss: no toilets, café or paved paths. The nearest services are in Mosfellsbær.

On the map

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Nearby places worth a stop

HelgufossHelgufossSmall waterfall on the Kaldakvísl river, in the same valleyÞórufossÞórufossQuiet waterfall on Route 48, towards Hvalfjörður
MosfellsdalurQuiet farming valley with horse farms, walking trails and the Laxness museum
Þingvellir National ParkÞingvellir National ParkContinue on Route 36 into the Golden CircleÖxarárfossÖxarárfossWaterfall inside Þingvellir National ParkEsjanEsjanThe mountain above Reykjavík, just north of the valley

Where to stay near Tröllafoss

Most people visit Tröllafoss as a short trip from Reykjavík rather than staying nearby.

Tröllafoss FAQ

Is Tröllafoss hard to find?

It's a local spot without much signage. Head for Skeggjastaðir farm in Mosfellsdalur and turn right onto Tröllafossslóði just before the farm. Save the directions before you go.

How long is the walk to the falls?

The walk from the parking area is short, but allow about an hour in total for the visit.

Is there a fee to visit?

No, Tröllafoss is free to visit.

Is it suitable for families?

Yes, though the path is uneven with stream crossings, so it suits families comfortable with an easy, informal walk.

Why is it called Tröllafoss?

The name means "Troll Waterfall". Rock formations in the cliff beside the falls are said to look like a troll's face.

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