The Gljúfrabúi waterfall or Gljúfurárfoss is situated at Hamragarðar close to it’s better known neighbour Seljalandsfoss waterfall, 1 kilometer from the mainroad. There are signs along the road pointing to a parking lot in front of the Seljalandsfoss.
When walking to the Seljalandsfoss, a little bit further (800 meters) Gljúfrabúi is situated. The only way to see the fall is to climb up the cliff in front it, because the fall is partially masked by its own canyon.
The waterfall Gljúfrabúi tumbles down from the Gljúfurá River over 60 meters. Its source is just north of Tröllagil (Troll Gorge) Canyon in the heath Hamragarðaheiði. It is a spring-fed river and less voluminous than its neighbour Seljalandsá River. The river runs from Tröllagilsmýri (Troll Gorge Marsh), a picturesque and fertile marsh in the heath. When the river emerges out of the marsh, it runs into the northern edge of a lava field which was formed in the volcanic eruptions in Eyjafjallajökull at the beginning of Holocene. There are several little waterfalls to be found in the river in the area.
Gljúfrabúi is on the land of the uninhabited farmstead Hamragarðar which the Rangá Foresty Society received as a gift in 1962 and is now owned by the municipality of Rangárþing eystra. There is a certain mystique over the waterfall because it falls into a deep chasm, while in front of it there is much palagonite rock that blocks the waterfall so that only the very top of it is visible. The boulder that blocks the waterfall is called Franskanef. Previously, people believed that it and the surrounding cliffs were the residences of huldufólk or hidden people. It is possible to climb onto Franskanef and see the waterfall from above. On the most risky parts there is a chain with which it is possible to support oneself; however, care must be taken if one climbs up and it is not for everybody. It is also possible to take off your shoes and wade the river down in the canyon. It’s an amazing experience. Caution must be taken when travelling in the canyon because there is a risk of falling rocks. There is an old bath basin below Franskanef and at the inner end of the basin there is a little cave called Ömpuhellir, named after a hermit woman who lived there. Gljúfrabúi is a protected natural monument.
A little south of Gljúfrabúi there is a small canyon in the cliff face from which it is possible to ascend onto the heath above where there is a spectacular view of the neighbouring area. People referred to it as going up Stígurinn (the Path) and thus the river in that canyon is named Stígslækur (Path Brook). The path is still rather clear, with some stairs where it is steepest. Right above the edge, there are ruins of old sheepcotes from Hamragarðar.
Info from Katla Geopark