Urðhæðavatn is 447 m above sea level and about 1.1 km² in area. It does not belong to the Arnarvatnsheiði fishing association, but to the land Gilsbakki. The lake is considered to be a good fishing lake and is an exciting option for anglers who make their way to the heath. It is northwest of Úlfsvatn and it is not far between the lake and Northern-Kvíslavatn. Reasonably fit anglers can easily walk to the lake.