Hafragilsfoss was the third of four major waterfalls on the glacial river Jökulsá á Fjöllum that we visited within the vast protected area of Vatnajökull National Park (formerly Jökulsárgljúfur National Park when we visited it in 2007). The falls was said to have a drop of 27m with an average width of 91m, and judging from the amount of mist it threw up as well as the muffled thundering sound that it made was a testament to the its size and volume. This was the third waterfall in the series of wateTh as it thunderously drops 27m.
The Jökulságljúfur canyon within the vicinity of the falls was said to be at its deepest. The power of the river was evident as we noticed a maze of gorges further downstream of the falls. It was this maze of gorges that probably reminded me the most of a miniature version of the real Grand Canyon in Arizona.
Like the other major waterfalls further upstream on the river Jökulsá á Fjöllum upstream, it was possible to experience this falls both sides of the river. However, we only witnessed this falls from the more accessible east side, and even then the view was distant making me wish I had a telephoto lens at the time.
Conversely on the west side, I had read that it was a bit of an adventure to get to the falls involving rope ladders and steep climbs. Without doing this climb, the literature had said that the view of the falls was marginal. The benefit of going through the trouble to do the 1.5- to 2-hour hike and scramble was that it promised put you right at the brink of the falls, but since we didn't do it, we can't really say for sure what it was like there.
Directions: From the turnoff leading to the east bank car park for Dettifoss (see that page for directions on getting there), continue north on Route 864 for another 2km where there's another signposted turnoff to the left. Take that turnoff and continue to the car park.
If you're interested in checking out the west bank of this waterfall, there's a turnoff branching off the spur road leading to Dettifoss. See that page for details.