Stóra-Björnsfell (in Icelandic pronounced as /ˈstouːra-ˈpjœr̥sˌfɛtl̥/) is an elongated medium-sized tuya located in Iceland. It contains pillow lava, hyaloclastite and sheet lava. The volcano formed when a subglacial eruption occurred beneath an ice sheet during the last ice age. Stóra-Björnsfell's pillow lava appears originally to have erupted from a fissure.