River Hengifossa discharges Lake Hengifossarvatn on the Fljotsdalsheidi moorland and spills into Lake Logurinn. Two main waterfalls decorate this river, the third highest of the country, Hengifoss (118m) and Litlanesfoss, framed with beautiful, long and regular basaltic pillars.

The basaltic strata surrounding The Hengifoss are interesting because of the thin, red layers of clay between the basaltic lavas. Fossilized trunks of coniferous trees, sensitive to cold, and lignite, which depict warmer climates during the latter part of Tertiary. It is possible to walk or rather climb behind it to inspect a small cave. The walk up to the waterfalls is relatively easy and well worth the effort.