The upper part of the river has the name Varma, but the lower part Thorleifslaekur. The river's course meanders calmly through the lowland areas and tributes to the largest river of the country, Olfusa, about 6 km from the ocean. Its sources are in the mountains beyond the horticultural town Hveragerdi, where the precipitation is almost at its greatest in the country.

Where it runs through the valley behind the town and on the outskirts of the town, quite some volume of natural hot water spills into it, making it the warmest river of the country. The catch consists of sea trout and char and late in summer some salmons as well. The fishing season for this river starts on April 1st.

The distance from the capital is about 35 km.