What is "esjan"

The mountain Esja , often called Esjan ("the Esja"), is situated in the south-west of Iceland, about 10 km to the north of Iceland's capital city Reykjavík. Esja is not a single mountain, but a volcanic mountain range, made from basalt and tuff. The etymology of the name is unclear. Esja can be used as a first name in Iceland. In the Kjalnesingasaga, there is a rich widow among Irish settlers named Esja, but it is likely that the women's name is derived from the mountain and not vice versa.