F249 Hvolsvöllur to Þórsmörk: Krossá Fords, 120 km

Þórsmörk — “Thor’s woodland” — is a startlingly green valley hemmed in by three glaciers: Eyjafjallajökull, Mýrdalsjökull and Tindfjallajökull. Getting there on the F249 is one of Iceland’s most demanding legal drives: the Krossá and other glacial rivers are unbridged, rise fast in the afternoon melt and change course, so a large 4×4 is essential — and river-crossing damage is not covered by rental insurance. Many people wisely take a highland bus or super-jeep instead. Summer only. You drive on the right.

Day 1 — Hvolsvöllur into Þórsmörk and back (60 km each way)

Turn off the Ring Road near Hvolsvöllur, passing Seljalandsfoss and the snout of Gígjökull, as the F249 works deeper into the valley with mounting fords that culminate in the notorious Krossá. Once in, walk up Valahnúkur for the classic panorama over the braided rivers and glaciers, or sample a stretch of the famous Laugavegur and Fimmvörðuháls trails. Drive back out before mid-afternoon, when meltwater makes the rivers highest and most dangerous.

Costs

Use the cost calculator to price fuel and the day for your exact dates. Budget a large 4×4 and fuel — or, honestly the smart choice for many, a seat on the Þórsmörk highland bus from Reykjavík or Hvolsvöllur, which fords the rivers for you. There are no tolls. Never attempt the Krossá in anything but a big 4×4, cross slowly and only when you are sure of the depth, and turn back if the river is in flood.

This trip is also in the free Roadcut trip planner: change the number of days and where you sleep each night, pick your vehicle to see the fuel cost, check the weather on the road, and open each day in Google Maps, Apple Maps or Waze.