Flateyjardalur

thumb|right|300px|Flateyjardalur 2018

Flateyjardalur () is a valley in northern Iceland by Skjálfandi bay on the Flateyjarskagi peninsula. The valley stretches from the coast and south to Fnjóskadalur valley. Flateyjardalur is named after the island of Flatey, which lies just off the shore. It is about 33 km long, almost straight with only a small bend at the end near the sea and has a direction almost perfectly from north to south.