Grabrok

Grabrok is the largest of three craters on a short fissure beside the ring road in Nordurardalur, about 170 metres high, formed roughly 3,400 years ago in an eruption that produced the lava field around it. A wooden staircase and boardwalk climb the side to a path round the rim, so the whole thing takes twenty minutes up and twenty back, which makes it one of the easiest craters in Iceland to stand on. The smaller neighbour Grabrokarfell was quarried for gravel before protection came in; Grabrok itself was protected in 1962. The rim gives a full view of the valley and the lava field.

What you'll find

• A crater about 170 metres high - the largest of three on one fissure.
• Steps and boardwalk to the rim - twenty minutes up.
• A quarried neighbour - Grabrokarfell, cut for gravel before protection.
• The lava field below - produced by the same eruption 3,400 years ago.

When to go

May to October; the steps are icy in winter. An hour.

What to expect

Staying on the boardwalk is required - the scoria erodes badly where people cut corners. The rim is windy and the path narrow in places. It is right beside a fast road and traffic noise carries. There is a car park with toilets at the foot and nothing on the crater itself.

Nearby

Glanni is a few minutes away; Reykholt and Husafell are east.

Key facts