The Blue Lagoon () is a geothermal spa in southwestern Iceland. The spa is located in a lava field near Grindavík and in front of Mount Þorbjörn on Reykjanes Peninsula, in a location favourable for geothermal power, and is supplied by water used in the nearby Svartsengi geothermal power station. The Blue Lagoon is approximately from Keflavík International Airport, and is one of the most visited attractions in Iceland.