Sundhnúksgígar or Sundhnúkagígar is a series of volcanic craters east of Eldvörp–Svartsengi in Iceland. They are named after Sundhnúkur, which is a hill just south of Sundhnúksgígar. The craters are aligned in a row called Sundhnúksgígaröðin. The first eruption of the crater row took place about 2000 years ago. There was volcanic activity nearby during the period known as the Reykjanes fires with the last previous eruption being about 1240 CE. In December 2023, as part of the Sundhnúkur eruptions, some craters began to erupt. On 14 January 2024, a second eruption began following seismic activity associated with the area of the Sundhnúksgígar craters. As of April 2025 there had been eight eruptions.