Þríhyrningur mountain is located on the north side of Fljótshlíð region in South Iceland. The mountain is 678 meters high and from there is a beautiful view to Eyjafjallajökull glacier to the south east, Tindfjallajökull glacier to east and Hekla volcano to north west.
The main rock formation is Tuff stone, telling us that Þríhyrningur mountain was formed during a time the land was covered by glaciers so the mountain is at least 12.000 years old.
The mountain plays a role in the saga Njálssaga, Flosi Þórðarson from Svínafell did hide there with his men before they went to Bergþórshvoll to burn down the farm where Njáll and his family lived.
To reach the foot of the mountain you need to drive Fljótshlíðarvegur from Hvolsvöllur and make a left turn by Tumastaðir, from there you need to drive into Vatnsdalur valley about 7 km to Fiská river to the parking where the hiking trail starts from. Please note that the road is closed during winter due to snow.
The hiking from the parking to the top of Þríhyrningur and back will take around 3 hours.