Skeiðarársandur is the name of the Black Sand area south of the glacier Skeiðarárjökull, the area is between the mountain Lómagnúpur in the west and Skaftafell in the east and it covers up around 600 square kilometres.
Skeiðarársandur is the floodplain from many glacier rivers flowing from down under Skeiðarárjökull glacier like the river Skeiðarár and Gígjukvísl, it is also the floodplain of glacier outburst (jökulhlaup) from some of the volcanoes located underneath the south part of Vatnajökull ice cap, like volcano Grímsvötn and Volcano Gjálp. The big glacial rivers were hard to cross in the old days when there were no bridges across so people had to ride across on horses. And if it was not possible they sometimes went across the Skeiðarárjökull glacier instead.
The bridge across the Skeiðarár river was built in the year 1974 and was the last bridge that was to complete the main road around Iceland. This bridge across the Skeiðarár river was around 1000 meters long and the longest bridge in Iceland. The bridge will be taken down in the next couple of years because of changing in the water flow from underneath the glaciers. Now all the water goes to the west side of the glacier and flows down another glacier river called Gígjukvísl, all this is because of global warming.
In 1996 there was a big subglacial volcanic eruption in the volcano Gjálp in the centre of Vatnajökull glacier that melted a lot of glacial ice so there came a big glacial outburst (jökulhlaup), estimated to be around 50.000 cubic meters per second from underneath the glacier.
It destroyed a part of the main road and the bridges across Skeiðarár river and Gígjukvísl river so they needed to rebuild the bridges and the roads. Since that time many things have changed because of melting of Skeiðará the river has no water anymore, now flowing different ways then before and the black sand area is growing quite fast with moss and birch trees.
The area is the home of birds like Great Skua as many others.
Note: Do not park or stop the car on the main road! Be careful when turning off the main road, slow down in time and give indicators.
Read more about Driving in Iceland.