Reykjanes (pronounced [ˈreiːcanɛs]) or Reykjanesskagi is a peninsula and a volcanic system situated at the south-western end of Iceland, near the capital of Reykjavík.

The peninsula is marked by active volcanism under its surface, and large lava fields, allowing little vegetation. There are numerous hot springs and sulphur springs in the southern half of the peninsula, around the Kleifarvatn lake and the Krýsuvík geothermal area.

There is also a geothermal power station at Svartsengi. Near the power station is a swimming pool has been installed using the hot and mineralized water coming down from the power station; it is known as the "Blue Lagoon" (Bláa Lónið).

The Leif the Lucky (or Miðlína) Bridge spans the Álfagjá rift valley (60 feet wide and 20 feet (6.1 m) deep) near Grindavik, which marks the boundary of the Eurasian and North American continental tectonic plates. It was built in 2002 and named in honor of Icelandic explorer Leif Eriksson who traveled from Europe to America 500 years before Columbus.