The Flatey Valley stretches from the northern part of the Fnjoska Valley all the way to the ocean in the North. In summer, it is accessible by a 4wd track over an elevation of 220 m of the marshland Flateyjardalsheidi. About midway across is a mountain hut, where it is possible to stay overnight. The descending slopes to the north are the discharge area of the good salmon and trout river Dalsa, which spills into the Skjalfanda Bay.

According to the Finnboga Saga 15 of Finnbogi's enemies ambushed him where the present road descends a narrow ridge. He was travelling there alone and managed to kill 12 of them before help came and drove the remaining three away. In earlier times, the valley contained five farms, which have all been abandoned. The family, who struggled the longest, did not leave the farm Brettingsstadir until 1954.

At Brettingsstadir stood a church for a period. The valley bottom is flat and fertile and extremely colourful and beautiful during summer. The winters are extreme and severe. The hardships and lack of communications drove the people, who lived there away.
Grenivik