A vast wetland area in the highlands, c.30 km north and west of Langjökull glacier, with extensive flat, eroded areas of gravel. Ownership of the highlands has not been resolved, but farmers hold grazing and fishing rights.
One of the main breeding areas of Cygnus cygnus in Iceland (e.g. 286 moulting on two lakes in Arnarvatnsheidi in 1976).
BirdLife International (2019) Important Bird Areas factsheet: Arnarvatnsheidi-Tvidaegra. Downloaded from http://www.birdlife.org on 11/11/2019.