{{Short description|Icelandic mountain}} {{more citations needed|date=August 2021}} {{Infobox mountain | name = Esja | image = Esja (2571116699).jpg | image_caption = The mountain range Esja | elevation_m = 914 | elevation_ref = | prominence_m = | prominence_ref = | listing = | location = 10 km north of [[Reykjavík]], [[Iceland]] | range = | map = Iceland | map_relief = 1 | range_coordinates = | map_size = 200 | label_position = right | coordinates = {{coord|64|15|N|21|38|W|type:mountain_region:IS_scale:100000|format=dms|display=inline,title}} | coordinates_ref = | type = | age = | volcanic_arc/belt = | last_eruption = | first_ascent = | easiest_route = [[hiking]] }} '''Esja''' ({{IPA|is|ˈɛːsja}}; often '''Esjan''' {{IPA|is|ˈɛːsjan|}}, with the [[Icelandic_grammar#Articles|feminine definite article]]) is a {{Convert|914|m|ft|0|abbr=on}} mountain situated in the south-west of [[Iceland]], about ten kilometres north of Iceland's capital city [[Reykjavík]].<ref>{{Cite web |title=Mt. Esja {{!}} Visit Reykjavík |url=https://visitreykjavik.is/mosfellsbaer/mt-esja |access-date=2025-12-12 |website=visitreykjavik.is |language=en}}</ref>
Esja is not a single mountain, but a [[volcanism|volcanic]] mountain range, made from [[basalt]] and [[tuff]]. [[File:Reykjavik Esja.jpg|thumb|Esja as seen from [[Perlan]]]] [[File:Steinn On Mt. Esja.JPG|thumb|Steinn on Esja]]
== Etymology == The name is likely related to an archaic word, {{lang|non|esja}}, meaning [[rock flake]] or carving stone.<ref>{{cite book|author=Ásgeir Blöndal Magnússon|url=https://malid.is/leit/Esja|title=Íslensk orðsifjabók|year=1989}}</ref>
In the ''[[Kjalnesinga saga]]'', there is a rich widow among Irish settlers named Esja, but it is likely that the woman's name is derived from the mountain and not vice versa.
''Esja'' can be used as a given name in Iceland.
==Formation== Esja was built up at the end of the [[Pleistocene]] with the beginning of the [[Last Glacial Period|Ice Age]]. During the warm periods [[lava]] flowed, and in the cold periods ridges of tuff were built up under the [[glacier]]. The western part of the mountain range is the oldest (about 3.2 million years) and the eastern part is the youngest (about 1.8 million years). The movements of the [[plate tectonics|plate boundaries]] cutting diagonally through Iceland are continually pushing the [[stratum|strata]] to the west and away from the active volcanic zone.<ref name="How did Esjan form">[https://www.visindavefur.is/svar.php?id=9057 Hvernig myndaðist Esjan?] Vísindavefurinn, 9 December 2008 (in Icelandic)</ref> [[Intrusion]]s, i.e. large [[magma]] channels coming from the old [[central volcano]]es at [[Kjalarnes]] and [[Stardalur]] {{IPA|is|ˈstarˌtaːlʏr̥|}}, found entrances into the strata.<ref name="How did Esjan form" /> The result was a series of large lava fields, one above the other, which the Ice Age glacier ground down.<ref name="How did Esjan form" /> It left only the highest summits, like the mountain ranges of Esja or [[Akrafjall]] {{IPA|is|ˈaːkraˌfjatl̥|}}.
==Physical features== {{unreferenced section|date=August 2021}} The easternmost summits of the mountain range, called Móskarðshnúkar {{IPA|is|ˈmouːˌskarðsˌn̥uːkʏr̥|}}, are of an unusually light colour. An Icelandic writer in the 19th century, so goes the story, hoped to see the sun there after a long period of rain. But when he looked closer, it was only the mountaintops with their colours. In reality, it is the [[rhyolite]] stone, often to be found in Icelandic nature near old (and also active) [[central volcano]]es.
== Hiking and climbing == Within easy reach of the capital, Esja is a very popular recreation area for hikers and climbers. The best known hiking paths lead to the summits Þverfellshorn {{IPA|is|ˈθvɛrˌfɛlsˌhɔ(r)tn̥|}} (780 m) and Kerhólakambur {{IPA|is|ˈcʰɛrˌhouːlaˌkʰampʏr̥|}} (851 m). Þverfellshorn is also easily accessible by public transport.
The path is divided into sections, marked with signs along the way. Each sign gives an indication of the difficulty of the path ahead with a grade system ranging from 1 boot (easy) to 3 boots (challenging). At the third sign experienced climbers can choose to climb directly to the peak, instead of following the path which goes off to the right.<ref name="Esjan - routes and history">[http://www.ferlir.is/?id=11602 Esjan - leiðir og saga] Ferlir.is (in Icelandic)</ref> After approximately 6.6 kilometers of walking and 597 meters altitude gain is a big rock called Steinn {{IPA|is|ˈsteitn̥|}}.<ref name="Esjan - routes and history" /> It is here that most inexperienced climbers choose to go down again, as the path becomes increasingly difficult from there.<ref name="Esjan - routes and history" />
The highest point, at 914 m, is called Hábunga {{IPA|is|ˈhauːˌpuŋka|}}.<ref name="Esjan - routes and history" /> From Þverfellshorn, reaching Hábunga requires another three-kilometer trek northeast, across a rocky plateau with no directional signs or clear path. As of June 2024, Hábunga was marked only by a large [[cairn]] with a wooden stick at the top.
There is danger of avalanches in wintertime. The last fatality was in 2020.<ref>[https://www.ruv.is/frett/man-died-in-avalanche Man died in avalanche] Rúv.is</ref>
{{wide image|Esja Þverfellshorn panoramic view of Reykjavík.jpg|800px|View from the [[Þverfellshorn]] peak towards [[Mosfellsbær]] and [[Reykjavík]]}}
== References == {{Reflist}}
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[[Category:Mountains of Iceland]] [[Category:Volcanoes of Iceland]] [[Category:Pliocene volcanoes]] [[Category:Pleistocene volcanoes]]