The mountain is the tallest subaerial stratovolcano in Iceland, at 1,833 m (6,014 ft),[8] and is immediately east of the Hálslón Reservoir of the Kárahnjúkar hydroelectric project and north of the Vatnajökull glacier with its Eyjabakkajökull tongue.

In addition to the main mountain, the Snæfell volcanic system has a series of fissures and smaller subglacial eruptive features, oriented in a south-west to north-east direction (27°), almost parallel to the active northern volcanic zone,[8] which is 45 km (28 mi) to its west.

[11] The basal tholeiitic basalt sheet bedrock age on which the volcano is built, is between 2.5 to 1.8 million years old and can be easily distinguished from the current volcano's magma source which is transitional alkalic, with no evidence of admixture with continental crust, as some had postulated might be the case.

[12][8] Recent work has suggested that the Upptyppingar subglacial volcano to its west has compositional similarities to Snæfell which helps the argument for a flank zone concept.

[10] Snæfell compositions have been studied in some detail as they help to understand mantle plume characteristics that may be related to the Iceland hotspot,[10] and magma evolution.