Southern Peninsula (Iceland) in the context of Litli-Hrútur

Fagradalsfjall (Icelandic: [ˈfaɣraˌtalsˌfjatl̥] ) is an active tuya volcano formed in the Last Glacial Period on the Reykjanes Peninsula, around 40 kilometres (25 mi) from Reykjavík, Iceland. Fagradalsfjall is also the name for the wider volcanic system covering an area 5 kilometres (3 mi) wide and 16 kilometres (10 mi) long between the Eldvörp–Svartsengi [ˈɛltvœr̥p–ˈsvar̥(t)sˌeiɲcɪ] and Krýsuvík systems. The highest summit in this area is Langhóll [ˈlauŋkˌhoutl̥] (385 m (1,263 ft)). No volcanic eruption had occurred for 815 years on the Reykjanes Peninsula until 19 March 2021 when a fissure vent appeared in Geldingadalir to the south of Fagradalsfjall mountain. The 2021 eruption was effusive and continued emitting fresh lava sporadically until 18 September 2021.

The eruption was unique among the volcanoes monitored in Iceland so far and it has been suggested that it could develop into a shield volcano. Due to its relative ease of access from Reykjavík, the volcano has become an attraction for local people and foreign tourists. Another eruption, very similar to the 2021 eruption, began on 3 August 2022, and ceased on 21 August 2022. A third eruption appeared to the north of Fagradalsfjall near Litli-Hrútur [ˈlɪhtlɪ-ˌr̥uːtʏr̥] on 10 July 2023, and ended on 5 August 2023.

Keflavík (pronounced [ˈcʰɛplaˌviːk] , meaning Driftwood Bay) is a town in the Reykjanes region in southwest Iceland. It is included in the municipality of Reykjanesbær whose population as of 2016 is 15,129.

In 1995, Keflavík merged with nearby Njarðvík and Hafnir to form the municipality of Reykjanesbær. Keflavík International Airport, the country's largest airport (serving nearby Reykjavík) is adjacent to the town.

The Reykjanes Peninsula (Icelandic: Reykjanesskagi [ˈreiːcaˌnɛːsˌskaijɪ]) in southwest Iceland is the continuation of the mostly submarine Reykjanes Ridge, a part of the Mid-Atlantic Ridge, on land and reaching from Esja in the north and Hengill in the east to Reykjanestá in the west. Suðurnes (transl. Southern Peninsula) is an administrative unit covering part of Reykjanes Peninsula.

A great deal of volcanic activity was occurring in the Reykjanes Peninsula in 2020 and into 2024, after nearly 800 years of inactivity. After the eruption of the Fagradalsfjall volcano on 19 March 2021, National Geographic's experts predicted that this "may mark the start of decades of volcanic activity". The eruption was small leading to a prediction that this volcano was unlikely to threaten "any population centers".

Eldvörp–Svartsengi (Icelandic pronunciation: [ˈɛltˌvœr̥p–ˈsvar̥(t)sˌeiɲcɪ]); "fire cones–black meadow" in Icelandic also Svartsengi volcanic system) is a volcanic system in the southwest of Iceland on the Southern Peninsula, southeast of Keflavík International Airport and north of the town of Grindavík. Made up of fissures, cones and volcanic craters, it had been relatively inactive for several centuries until 2020, when the first in a series of magmatic intrusions occurred. In December 2023 the fourth such intrusion culminated in an eruption, with further eruptions in 2024 and 2025.