Lake Oddastaðavatn is in an extremely beautiful environment in Hnappadalur on the west side of Hlíðarvatn. This is a good fishing lake, about 3 km² in area and has been measured at a maximum depth of about 18 m, although the average depth is much less. Height above sea level is about 57 m. The Hraunholtsá river flows into the lake from Hlíðarvatn and from it flows the nationally famous salmon river Haffjarðará. Both brown trout and Arctic char are in the lake and there are good populations of fish. The trout can be big, but the char is usually quite small. Two islets, separated by a narrow channel, adorn Oddastaðavatn.