Keriš is the northernmost crater in a row of small craters called Tjarnarholar. They blasted ca. 6500 years ago, and resides half way between Selfoss and the Geysir in Reykholt.
Keriš measures 270x170m, is 55m deep, while the watery eye on its bottom has a depth of 7-14m, depending on the amount of precipitation,
melting snow and the time of the year. You can clearly see the shorelines of different water levels surrounding the pond.