Igarashi, Ikarashi or Isoarashi is a Japanese surname. This surname said to have origin Ikarashi river, that flows in central Niigata Prefecture. The name of Ikarashi comes from the ancient legend of Yamato prince Ikatarashihiko-no-mikoto (五十日足彦命), pioneer of this region, or Ainu word Inkar-us-i.
