Kvarnmyrorna is a 215-hectare reserve of forest and bog about 19 kilometres northwest of Hassela, in Nordanstig municipality. The Kölån runs through it and is classified as nationally particularly valuable water. There are no paths or trails through the reserve, and much of it is wet bogland.

The bog is an undisturbed complex of sloping fens. Forest grows on patches of firm ground and around the edges, including pine- and spruce-dominated woodland with trees 200 to 300 years old. The reserve also has damp, shaded stream environments. Red-listed lichens and fungi have been found here, including the rare and critically endangered trådbrosklav lichen, on spruce beside streams in the north.

It says motor vehicles are allowed only on roads intended for motor traffic. Taking firewood is prohibited, and fires are allowed only with wood brought in by the visitor. Visitors must not damage trees or shrubs, collect plants, fungi or lichens, or disturb wildlife.