The research of sinter shows that Geysir has been active for approximately 10,000 years. The oldest accounts of hot springs at Haukadalur date back to 1294, when earthquakes in the area caused significant changes in local neighboring landscape creating several new hot springs. Changes in the activity of the Geysir and the surrounding geysers are strongly related to earthquake activity. In records dated 1630 the geysers erupted so violently that the valley around them trembled. The placename "Geysir" has been first mentioned in written sources in 18th century and, as unusual natural phenomena were of high interest to the society during the Age of Enlightenment, the term became popular and has been used for similar hydrothermal features worldwide since then.
In 1845, it reaches a height of 170 metres. In 1846 the research of Geysir by Robert Bunsen results with the explanation of the mechanism of geyser activity. Measurements of professor Bunsen in this year show that Geysir was erupting 43 - 54 m high.
History of recent centuries shows that earthquakes have tended to revive the activity of Geysir which then subsides again in the following years. Before 1896, Geysir was almost dormant before an earthquake that year caused eruptions to begin again, occurring several times a day, lasting up to an hour and causing spouts of up to 60 metres in height. In 1910, it was active every 30 minutes; five years later the time between the eruptions was as much as six hours, and in 1916, the eruptions all but ceased. In 1935 a man made channel was dug through the silica rim around the edge of the geyser vent. This ditch caused a lowering of the water table and a revival in activity. Gradually this channel became too clogged with silica and eruptions again became rare. In 1981 the ditch was cleared again and eruptions could be stimulated, on special occasions, by the addition of soap. Following environmental concerns the practice of adding soap was seldom employed
