Adiantum aleuticum (western maidenhair fern) is a species of fern in the genus Adiantum, native mainly to western North America from the Aleutian Islands of Alaska, south to Chihuahua, and also locally in northeastern North America from Newfoundland south to Maryland. The fronds grow to 15-110 centimeter high, and are fan-shaped, light to medium green with dark brown to black stems. It prefers fertile, moist soil in rock crevices near streams, from sea level in the north of its range, up to 3,200 meter altitude in the south of its range. It tolerates serpentinite rock well, and is confined to this mineral-rich rock in some areas.