Hvítá, Árnessýsla
Hvítá (engl. white river) is a river whose source is in the glacier lake Hvítárvatn at Langjökull glacier in the highlands of Iceland at 64°37′N 19°50′W / 64.617°N 19.833°WCoordinates: 64°37′N 19°50′W / 64.617°N 19.833°W. The river flows for 40 km (25 mi) before dropping down into a narrow gorge at the Gullfoss waterfall.
After this, the river flows between the Biskupstungur and Hrunamannahreppur districts. Here, one can find the confluence of the Hvítá and three other rivers: the Tungufljót, the Brúará, and the Stóra-Laxá. After this confluence the river contains double the amount of water compared to the amount at Gullfoss. The river then runs down through the flatlands near Grímsness and behind Ingólfsfjall mountain. Just north of the town Selfoss it joins the Sog River. After that the combined river is called the Ölfusá as it flows into the Atlantic Ocean.
Because of the danger of flooding, especially in the wintertime, it has the reputation of being the most dangerous river of Iceland.
There are organised rafting excursions on parts of this river.