Hvítá (Icelandic [ˈkʰviːtˌauː], "white river") is a river in Iceland that begins at the Hvítárvatn glacier lake on the Langjökull glacier in the highlands of Iceland at 64°37′N 19°50′W / 64.617°N 19.833°W. The river flows for 40 kilometres (25 mi) before dropping down into a narrow gorge at the Gullfoss waterfall. Because of the danger of flooding, especially in the winter, it has the reputation of being the most dangerous river in Iceland. Organised rafting excursions take place on parts of the river.