The subglacial Esjufjöll (Icelandic pronunciation: [ˈɛːsjʏˌfjœtl̥] ⓘ) volcano is located in the south-east part of the Vatnajökull icecap.

[5] The highest part of volcano is an ice-covered ridge called Snæhetta, whose assigned height is lower than previous figures, at 1,745 m (5,725 ft)[3][a].

[6][7]: 185  In the second half of the 20th century, a number of small nunataks appeared as the more southern ice cover decreased; and two of the largest are named Bræðrasker and Kárasker.

The latest data is suggestive of a volcano that may be 20 km (12 mi) in diameter and its northern part is underlain by a dense intrusive body.

[11] In the beginning of September 1927, a glacial flood (jökulhlaup) came down the Jökulsá á Breiðamerkursandi (a short river from Breiðamerkurjökull to the sea).