Hólmasárfoss would not be your goal of the day, but you can spend some nice moments here. Not because you can find a tiny parking lot and toilets..
How to find Hólmsárfoss:
Hólmsárfoss in right by F232 in Icelandic highlands.
GPS coordinates of Hólmsárfoss Waterfalls : 63.710126, -18.720519 Take me there!
Photos of the Hólmsárfoss waterfall:
The Nearest Waterfalls