A fairy ring, also known as fairy circle, elf circle or pixie ring, is a naturally occurring ring or arc of mushrooms. The rings may grow over ten meters in diameter and become stable over time as the fungus grows and seeks food underground. They are found mainly in forested areas, but also appear in grasslands or rangelands. Fairy rings are not only detectable by sporocarps in rings or arcs, but also by a necrotic zone (dead grass) or a ring of dark green grass. If these manifestations are visible a fairy fungus mycelium is likely present in the ring or arc underneath.
Fairy rings also occupy a prominent place in European folklore as the location of gateways into elfin kingdoms, or places where elves gather and dance.