Drejskoven is a narrow forest on Ærø that lies right next to the Baltic Sea.
The forest lies on a dammed seabed, and provides shelter for the dammed area Gråsten Nor.
It contains many tree species, but appears mostly as a pine forest; Austrian pine, forest pine, mountain pine and dune pine, but also hardwoods such as oak, poplar, birch, linden and maple.
Drejskoven, which is now a state forest, was planted in 1915-1916 on an area between Gråsten Nor and Kysten. The land was sold from the Gråsten manor - a total of 34 acres of land which was sold on shares to mainly Marstal's sailors who did the planting as employment work as they could not sail due to the war.
There are two rest areas by the road, and there is a public toilet at the westernmost one.