Geysir (sometimes known as The Great Geysir) is a geyser in Iceland. It is in the Haukadalur valley, Iceland. It is the oldest known geyser and one of the world's most impressive ones. The English word "geyser" comes from Geysir. Geysir is on the slopes of Laugarfjall hill at . The Strokkur geyser is about 400 metres south of Geysir.