The 1070 km² catchment area of the glacial river Markarfljot has to be forded on The Middle Route. The river is about 100 km long and when it is swollen with meltwater it can become an obstacle and difficult to tackle.
Its 200 m deep canyon above the confluence of river Sydri-Emstrua is one of the sights worth seeing. This river used to create havoc in the lowlands by wandering about and changing its course before it was hemmed in with dikes and bridged in 1934 near road to Thorsmork wear you can see waterfall Seljalandsfoss
. The old bridge has been demolished. White water rafting on the river enjoys an increasing popularity.