Location of the Sprengisandur highland area Sprengisandur is a highland plateau in Iceland, defined roughly as the area between the Hofsjökull and Vatnajökull glaciers.
Like Kjölur and Kaldidalur, Sprengisandur is an ancient pass – during the time of the Icelandic Free State (ca. 930–1265) it was one of the several important north-south routes that connected remote regions of the island to the Plains of the Parliament, Þingvellir, where the yearly parliament, Alþingi, was held each year at midsummer. In the sagas of Icelanders it is often called simply Sandr “Sand” or Sandleið, “Sand trail”. At its southern end, it was joined with another such route, Fjallabaksvegur nyrðri, running west from Landmannalaugar mountain hot springs area. Sprengisandur is only accessible during summer – like other parts of the inner desert, it is impassable in winter because of the snow, and in spring because of floods. While being the shortest way to the Alþingi for some Icelanders, for example, those living around lake Ljósavatn that is very close to the northern end of the route, and for inhabitants of Vopnafjörður, it had the downside of having by far the longest stretch through the forbidding inner desert regions among the other possible routes. For hundreds of kilometers, there was no fodder for horses to be had, and no human habitation to take shelter in. This feature gave the area its name: it is derived from Icelandic noun sandur “sand”, which denotes the volcanic ash deserts of the center of the island, and the verb sprengja that means “to ride a horse to death; to be on the point of bursting after running for too long”. One needed to ride as fast as possible, nearly driving the horses to death, to cross the mountain desert and reach the inhabited regions of the island again before one ran out of victuals. Hence, Sprengisandur was, if at all possible, avoided by medieval Icelanders, even if it meant taking the longer route. As usual with uninhabited places in Iceland, Sprengisandur route was considered to be haunted by ghosts. Both themes, the difficulty of passage and the presence of ghosts, are referred to in the famous Icelandic song Á Sprengisandi, written by Grímur Thomsen (1820–1896)