Lake Ljósavatn is 3.2 km² in area, 35 m at its deepest and is 105 m above sea level. The inflow is from Geitá, Litlutjarnarlækur and river Kambsá and the outflow is river Djúpá, which flows to the river Skjálfandafljót. Most of the fish are char, ½-1 pound, and a considerable number of brown trout, which can be quite large. There is some net fishing in the lake, but probably too little, because the char is small, and the lake is considered overcrowded. Highway no. 1 lies along the lake through Ljósavatnsskarð and it is possible to drive around it. It is very popular with anglers and very suitable for families. The fishing is usually best in the spring, from May to mid-July. There are good fishing spots on the east side of the lake, at the mouth of small streams and where the river Kambsá falls into it.