Thjorsardalur

Thjorsardalur opens north of the Thjorsa river below Hekla, and its history is one eruption: in 1104 Hekla covered the valley in tephra and the farms in it were abandoned, some of them not excavated until the 1930s. The best known, Stong, was dug out and roofed, and a full reconstruction of it - Thjodveldisbaerinn, the Commonwealth Farm - was built nearby and opened in 1974 for the eleven hundredth anniversary of settlement. The valley also holds Haifoss and Granni at its head, the green ravine of Gjain, and Hjalparfoss at its mouth, so it works as a day rather than a stop. Forestry has been planted across the tephra since the middle of the last century.

What you actually see

• A valley emptied by Hekla in 1104 - farms buried in tephra and abandoned.
• Stong and its reconstruction - the excavated farm and the Commonwealth Farm of 1974.
• Haifoss, Gjain and Hjalparfoss - the valley's three set pieces.
• Planted forest on ash - the reclamation work of recent decades.

When to go

June to September; the gravel side roads are shut much of the rest of the year. A full day.

Honest expectations

Roads 327 and 332 are rough gravel with fords in places and hire car agreements often exclude them. The reconstruction keeps short summer hours. Ash and dust blow hard in dry wind. Facilities are minimal outside the campsite.

Nearby

Hekla stands above the valley; Landmannalaugar lies beyond it inland.