Jökulsárlón is a large glacial lake in southeast Iceland, on the edge of Vatnajökull National Park. Situated at the head of the Breiðamerkurjökull glacier, it developed into a lake after the glacier started receding from the edge of the Atlantic Ocean. The lake has grown since then at varying rates because of melting of the glaciers. It is now 1.5 kilometres away from the ocean's edge and covers an area of about 18 km2. It recently became the deepest lake in Iceland, at over 248 metres, as glacial retreat extended its boundaries. The size of the lake has increased fourfold since the 1970s. It is considered as one of the natural wonders of Iceland.

The lake can be seen from Highway 1 between Höfn and Skaftafell. It appears as "a ghostly procession of luminous blue icebergs".

Jökulsárlón has been a setting for four Hollywood movies: A View to a Kill, Die Another Day, Tomb Raider and Batman Begins, as well as the "reality TV" series Amazing Race. 

The tongue of the Breiðamerkurjökull glacier is a major attraction for tourists. Tour operators conduct snowmobile and jeep tours to visit the glacier along the winding iceberg-studded Jökulsárlón. The base station for visits to the area is at Joklasel, which is approached from Höfn.

Vatnajökull also known as the Vatna Glacier, is the largest and most voluminous Icelandic glacier, and one of the largest in area in Europe. It is located in the south-east of the island, covering more than 8 percent of the country.

Vatnajökull National Park is one of three national parks in Iceland. It encompasses all of Vatnajökull glacier and extensive surrounding areas. These include the national parks previously existing at Skaftafell in the southwest and Jökulsárgljúfur in the north.

In general, national parks are protected areas which are considered unique because of their nature or cultural heritage. The unique qualities of Vatnajökull National Park are primarily its great variety of landscape features, created by the combined forces of rivers, glacial ice, and volcanic and geothermal activity.