Stóra-Eldborg undir Geitahlíð (also: Stóra-Eldborg við Geitahlíð) is a small Holocene volcano in Iceland, on Reykjanes peninsula, 50 m high, with a 30 m deep crater. It is located at about 5 km from Krýsuvík and as the name says at the foot of a bigger mountain, the tuya of Geitahlíð.